RedBlackBST
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代码很长，但是封装的很好，肯定不会错。 有一堆又一堆的异常处理。 效率远不如C++的红黑树。
import java.util.NoSuchElementException;
import java.util.ArrayList;
import java.util.InputMismatchException;
import java.util.Locale;
import java.util.Scanner;
import java.util.regex.Pattern;
import java.util.Iterator;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
public class RedBlackBST<Key extends Comparable<Key>, Value> {
private static final boolean RED = true;
private static final boolean BLACK = false;
private Node root; // root of the BST
// BST helper node data type
private class Node {
private Key key; // key
private Value val; // associated data
private Node left, right; // links to left and right subtrees
private boolean color; // color of parent link
private int size; // subtree count
public Node(Key key, Value val, boolean color, int size) {
this.key = key;
this.val = val;
this.color = color;
this.size = size;
}
}
/**
* Initializes an empty symbol table.
*/
public RedBlackBST() {
}
/***************************************************************************
* Node helper methods.
***************************************************************************/
// is node x red; false if x is null ?
private boolean isRed(Node x) {
if (x == null)
return false;
return x.color == RED;
}
// number of node in subtree rooted at x; 0 if x is null
private int size(Node x) {
if (x == null)
return 0;
return x.size;
}
/**
* Returns the number of key-value pairs in this symbol table.
*
* @return the number of key-value pairs in this symbol table
*/
public int size() {
return size(root);
}
/**
* Is this symbol table empty?
*
* @return {@code true} if this symbol table is empty and {@code false}
* otherwise
*/
public boolean isEmpty() {
return root == null;
}
/***************************************************************************
* Standard BST search.
***************************************************************************/
/**
* Returns the value associated with the given key.
*
* @param key
* the key
* @return the value associated with the given key if the key is in the symbol
* table and {@code null} if the key is not in the symbol table
* @throws IllegalArgumentException
* if {@code key} is {@code null}
*/
public Value get(Key key) {
if (key == null)
throw new IllegalArgumentException("argument to get() is null");
return get(root, key);
}
// value associated with the given key in subtree rooted at x; null if no such
// key
private Value get(Node x, Key key) {
while (x != null) {
int cmp = key.compareTo(x.key);
if (cmp < 0)
x = x.left;
else if (cmp > 0)
x = x.right;
else
return x.val;
}
return null;
}
/**
* Does this symbol table contain the given key?
*
* @param key
* the key
* @return {@code true} if this symbol table contains {@code key} and
* {@code false} otherwise
* @throws IllegalArgumentException
* if {@code key} is {@code null}
*/
public boolean contains(Key key) {
return get(key) != null;
}
/***************************************************************************
* Red-black tree insertion.
***************************************************************************/
/**
* Inserts the specified key-value pair into the symbol table, overwriting the
* old value with the new value if the symbol table already contains the
* specified key. Deletes the specified key (and its associated value) from this
* symbol table if the specified value is {@code null}.
*
* @param key
* the key
* @param val
* the value
* @throws IllegalArgumentException
* if {@code key} is {@code null}
*/
public void put(Key key, Value val) {
if (key == null)
throw new IllegalArgumentException("first argument to put() is null");
if (val == null) {
delete(key);
return;
}
root = put(root, key, val);
root.color = BLACK;
// assert check();
}
// insert the key-value pair in the subtree rooted at h
private Node put(Node h, Key key, Value val) {
if (h == null)
return new Node(key, val, RED, 1);
int cmp = key.compareTo(h.key);
if (cmp < 0)
h.left = put(h.left, key, val);
else if (cmp > 0)
h.right = put(h.right, key, val);
else
h.val = val;
// fix-up any right-leaning links
if (isRed(h.right) && !isRed(h.left))
h = rotateLeft(h);
if (isRed(h.left) && isRed(h.left.left))
h = rotateRight(h);
if (isRed(h.left) && isRed(h.right))
flipColors(h);
h.size = size(h.left) + size(h.right) + 1;
return h;
}
/***************************************************************************
* Red-black tree deletion.
***************************************************************************/
/**
* Removes the smallest key and associated value from the symbol table.
*
* @throws NoSuchElementException
* if the symbol table is empty
*/
public void deleteMin() {
if (isEmpty())
throw new NoSuchElementException("BST underflow");
// if both children of root are black, set root to red
if (!isRed(root.left) && !isRed(root.right))
root.color = RED;
root = deleteMin(root);
if (!isEmpty())
root.color = BLACK;
// assert check();
}
// delete the key-value pair with the minimum key rooted at h
private Node deleteMin(Node h) {
if (h.left == null)
return null;
if (!isRed(h.left) && !isRed(h.left.left))
h = moveRedLeft(h);
h.left = deleteMin(h.left);
return balance(h);
}
/**
* Removes the largest key and associated value from the symbol table.
*
* @throws NoSuchElementException
* if the symbol table is empty
*/
public void deleteMax() {
if (isEmpty())
throw new NoSuchElementException("BST underflow");
// if both children of root are black, set root to red
if (!isRed(root.left) && !isRed(root.right))
root.color = RED;
root = deleteMax(root);
if (!isEmpty())
root.color = BLACK;
// assert check();
}
// delete the key-value pair with the maximum key rooted at h
private Node deleteMax(Node h) {
if (isRed(h.left))
h = rotateRight(h);
if (h.right == null)
return null;
if (!isRed(h.right) && !isRed(h.right.left))
h = moveRedRight(h);
h.right = deleteMax(h.right);
return balance(h);
}
/**
* Removes the specified key and its associated value from this symbol table (if
* the key is in this symbol table).
*
* @param key
* the key
* @throws IllegalArgumentException
* if {@code key} is {@code null}
*/
public void delete(Key key) {
if (key == null)
throw new IllegalArgumentException("argument to delete() is null");
if (!contains(key))
return;
// if both children of root are black, set root to red
if (!isRed(root.left) && !isRed(root.right))
root.color = RED;
root = delete(root, key);
if (!isEmpty())
root.color = BLACK;
// assert check();
}
// delete the key-value pair with the given key rooted at h
private Node delete(Node h, Key key) {
// assert get(h, key) != null;
if (key.compareTo(h.key) < 0) {
if (!isRed(h.left) && !isRed(h.left.left))
h = moveRedLeft(h);
h.left = delete(h.left, key);
} else {
if (isRed(h.left))
h = rotateRight(h);
if (key.compareTo(h.key) == 0 && (h.right == null))
return null;
if (!isRed(h.right) && !isRed(h.right.left))
h = moveRedRight(h);
if (key.compareTo(h.key) == 0) {
Node x = min(h.right);
h.key = x.key;
h.val = x.val;
// h.val = get(h.right, min(h.right).key);
// h.key = min(h.right).key;
h.right = deleteMin(h.right);
} else
h.right = delete(h.right, key);
}
return balance(h);
}
/***************************************************************************
* Red-black tree helper functions.
***************************************************************************/
// make a left-leaning link lean to the right
private Node rotateRight(Node h) {
// assert (h != null) && isRed(h.left);
Node x = h.left;
h.left = x.right;
x.right = h;
x.color = x.right.color;
x.right.color = RED;
x.size = h.size;
h.size = size(h.left) + size(h.right) + 1;
return x;
}
// make a right-leaning link lean to the left
private Node rotateLeft(Node h) {
// assert (h != null) && isRed(h.right);
Node x = h.right;
h.right = x.left;
x.left = h;
x.color = x.left.color;
x.left.color = RED;
x.size = h.size;
h.size = size(h.left) + size(h.right) + 1;
return x;
}
// flip the colors of a node and its two children
private void flipColors(Node h) {
// h must have opposite color of its two children
// assert (h != null) && (h.left != null) && (h.right != null);
// assert (!isRed(h) && isRed(h.left) && isRed(h.right))
// || (isRed(h) && !isRed(h.left) && !isRed(h.right));
h.color = !h.color;
h.left.color = !h.left.color;
h.right.color = !h.right.color;
}
// Assuming that h is red and both h.left and h.left.left
// are black, make h.left or one of its children red.
private Node moveRedLeft(Node h) {
// assert (h != null);
// assert isRed(h) && !isRed(h.left) && !isRed(h.left.left);
flipColors(h);
if (isRed(h.right.left)) {
h.right = rotateRight(h.right);
h = rotateLeft(h);
flipColors(h);
}
return h;
}
// Assuming that h is red and both h.right and h.right.left
// are black, make h.right or one of its children red.
private Node moveRedRight(Node h) {
// assert (h != null);
// assert isRed(h) && !isRed(h.right) && !isRed(h.right.left);
flipColors(h);
if (isRed(h.left.left)) {
h = rotateRight(h);
flipColors(h);
}
return h;
}
// restore red-black tree invariant
private Node balance(Node h) {
// assert (h != null);
if (isRed(h.right))
h = rotateLeft(h);
if (isRed(h.left) && isRed(h.left.left))
h = rotateRight(h);
if (isRed(h.left) && isRed(h.right))
flipColors(h);
h.size = size(h.left) + size(h.right) + 1;
return h;
}
/***************************************************************************
* Utility functions.
***************************************************************************/
/**
* Returns the height of the BST (for debugging).
*
* @return the height of the BST (a 1-node tree has height 0)
*/
public int height() {
return height(root);
}
private int height(Node x) {
if (x == null)
return -1;
return 1 + Math.max(height(x.left), height(x.right));
}
/***************************************************************************
* Ordered symbol table methods.
***************************************************************************/
/**
* Returns the smallest key in the symbol table.
*
* @return the smallest key in the symbol table
* @throws NoSuchElementException
* if the symbol table is empty
*/
public Key min() {
if (isEmpty())
throw new NoSuchElementException("called min() with empty symbol table");
return min(root).key;
}
// the smallest key in subtree rooted at x; null if no such key
private Node min(Node x) {
// assert x != null;
if (x.left == null)
return x;
else
return min(x.left);
}
/**
* Returns the largest key in the symbol table.
*
* @return the largest key in the symbol table
* @throws NoSuchElementException
* if the symbol table is empty
*/
public Key max() {
if (isEmpty())
throw new NoSuchElementException("called max() with empty symbol table");
return max(root).key;
}
// the largest key in the subtree rooted at x; null if no such key
private Node max(Node x) {
// assert x != null;
if (x.right == null)
return x;
else
return max(x.right);
}
/**
* Returns the largest key in the symbol table less than or equal to
* {@code key}.
*
* @param key
* the key
* @return the largest key in the symbol table less than or equal to {@code key}
* @throws NoSuchElementException
* if there is no such key
* @throws IllegalArgumentException
* if {@code key} is {@code null}
*/
public Key floor(Key key) {
if (key == null)
throw new IllegalArgumentException("argument to floor() is null");
if (isEmpty())
throw new NoSuchElementException("called floor() with empty symbol table");
Node x = floor(root, key);
if (x == null)
return null;
else
return x.key;
}
// the largest key in the subtree rooted at x less than or equal to the given
// key
private Node floor(Node x, Key key) {
if (x == null)
return null;
int cmp = key.compareTo(x.key);
if (cmp == 0)
return x;
if (cmp < 0)
return floor(x.left, key);
Node t = floor(x.right, key);
if (t != null)
return t;
else
return x;
}
/**
* Returns the smallest key in the symbol table greater than or equal to
* {@code key}.
*
* @param key
* the key
* @return the smallest key in the symbol table greater than or equal to
* {@code key}
* @throws NoSuchElementException
* if there is no such key
* @throws IllegalArgumentException
* if {@code key} is {@code null}
*/
public Key ceiling(Key key) {
if (key == null)
throw new IllegalArgumentException("argument to ceiling() is null");
if (isEmpty())
throw new NoSuchElementException("called ceiling() with empty symbol table");
Node x = ceiling(root, key);
if (x == null)
return null;
else
return x.key;
}
// the smallest key in the subtree rooted at x greater than or equal to the
// given key
private Node ceiling(Node x, Key key) {
if (x == null)
return null;
int cmp = key.compareTo(x.key);
if (cmp == 0)
return x;
if (cmp > 0)
return ceiling(x.right, key);
Node t = ceiling(x.left, key);
if (t != null)
return t;
else
return x;
}
/**
* Return the kth smallest key in the symbol table.
*
* @param k
* the order statistic
* @return the {@code k}th smallest key in the symbol table
* @throws IllegalArgumentException
* unless {@code k} is between 0 and <em>n</em>鈥�1
*/
public Key select(int k) {
if (k < 0 || k >= size()) {
throw new IllegalArgumentException("called select() with invalid argument: " + k);
}
Node x = select(root, k);
return x.key;
}
// the key of rank k in the subtree rooted at x
private Node select(Node x, int k) {
// assert x != null;
// assert k >= 0 && k < size(x);
int t = size(x.left);
if (t > k)
return select(x.left, k);
else if (t < k)
return select(x.right, k - t - 1);
else
return x;
}
/**
* Return the number of keys in the symbol table strictly less than {@code key}.
*
* @param key
* the key
* @return the number of keys in the symbol table strictly less than {@code key}
* @throws IllegalArgumentException
* if {@code key} is {@code null}
*/
public int rank(Key key) {
if (key == null)
throw new IllegalArgumentException("argument to rank() is null");
return rank(key, root);
}
// number of keys less than key in the subtree rooted at x
private int rank(Key key, Node x) {
if (x == null)
return 0;
int cmp = key.compareTo(x.key);
if (cmp < 0)
return rank(key, x.left);
else if (cmp > 0)
return 1 + size(x.left) + rank(key, x.right);
else
return size(x.left);
}
/***************************************************************************
* Range count and range search.
***************************************************************************/
/**
* Returns all keys in the symbol table as an {@code Iterable}. To iterate over
* all of the keys in the symbol table named {@code st}, use the foreach
* notation: {@code for (Key key : st.keys())}.
*
* @return all keys in the symbol table as an {@code Iterable}
*/
public Iterable<Key> keys() {
if (isEmpty())
return new Queue<Key>();
return keys(min(), max());
}
/**
* Returns all keys in the symbol table in the given range, as an
* {@code Iterable}.
*
* @param lo
* minimum endpoint
* @param hi
* maximum endpoint
* @return all keys in the sybol table between {@code lo} (inclusive) and
* {@code hi} (inclusive) as an {@code Iterable}
* @throws IllegalArgumentException
* if either {@code lo} or {@code hi} is {@code null}
*/
public Iterable<Key> keys(Key lo, Key hi) {
if (lo == null)
throw new IllegalArgumentException("first argument to keys() is null");
if (hi == null)
throw new IllegalArgumentException("second argument to keys() is null");
Queue<Key> queue = new Queue<Key>();
// if (isEmpty() || lo.compareTo(hi) > 0) return queue;
keys(root, queue, lo, hi);
return queue;
}
// add the keys between lo and hi in the subtree rooted at x
// to the queue
private void keys(Node x, Queue<Key> queue, Key lo, Key hi) {
if (x == null)
return;
int cmplo = lo.compareTo(x.key);
int cmphi = hi.compareTo(x.key);
if (cmplo < 0)
keys(x.left, queue, lo, hi);
if (cmplo <= 0 && cmphi >= 0)
queue.enqueue(x.key);
if (cmphi > 0)
keys(x.right, queue, lo, hi);
}
/**
* Returns the number of keys in the symbol table in the given range.
*
* @param lo
* minimum endpoint
* @param hi
* maximum endpoint
* @return the number of keys in the sybol table between {@code lo} (inclusive)
* and {@code hi} (inclusive)
* @throws IllegalArgumentException
* if either {@code lo} or {@code hi} is {@code null}
*/
public int size(Key lo, Key hi) {
if (lo == null)
throw new IllegalArgumentException("first argument to size() is null");
if (hi == null)
throw new IllegalArgumentException("second argument to size() is null");
if (lo.compareTo(hi) > 0)
return 0;
if (contains(hi))
return rank(hi) - rank(lo) + 1;
else
return rank(hi) - rank(lo);
}
/***************************************************************************
* Check integrity of red-black tree data structure.
***************************************************************************/
private boolean check() {
if (!isBST())
StdOut.println("Not in symmetric order");
if (!isSizeConsistent())
StdOut.println("Subtree counts not consistent");
if (!isRankConsistent())
StdOut.println("Ranks not consistent");
if (!is23())
StdOut.println("Not a 2-3 tree");
if (!isBalanced())
StdOut.println("Not balanced");
return isBST() && isSizeConsistent() && isRankConsistent() && is23() && isBalanced();
}
// does this binary tree satisfy symmetric order?
// Note: this test also ensures that data structure is a binary tree since order
// is strict
private boolean isBST() {
return isBST(root, null, null);
}
// is the tree rooted at x a BST with all keys strictly between min and max
// (if min or max is null, treat as empty constraint)
// Credit: Bob Dondero's elegant solution
private boolean isBST(Node x, Key min, Key max) {
if (x == null)
return true;
if (min != null && x.key.compareTo(min) <= 0)
return false;
if (max != null && x.key.compareTo(max) >= 0)
return false;
return isBST(x.left, min, x.key) && isBST(x.right, x.key, max);
}
// are the size fields correct?
private boolean isSizeConsistent() {
return isSizeConsistent(root);
}
private boolean isSizeConsistent(Node x) {
if (x == null)
return true;
if (x.size != size(x.left) + size(x.right) + 1)
return false;
return isSizeConsistent(x.left) && isSizeConsistent(x.right);
}
// check that ranks are consistent
private boolean isRankConsistent() {
for (int i = 0; i < size(); i++)
if (i != rank(select(i)))
return false;
for (Key key : keys())
if (key.compareTo(select(rank(key))) != 0)
return false;
return true;
}
// Does the tree have no red right links, and at most one (left)
// red links in a row on any path?
private boolean is23() {
return is23(root);
}
private boolean is23(Node x) {
if (x == null)
return true;
if (isRed(x.right))
return false;
if (x != root && isRed(x) && isRed(x.left))
return false;
return is23(x.left) && is23(x.right);
}
// do all paths from root to leaf have same number of black edges?
private boolean isBalanced() {
int black = 0; // number of black links on path from root to min
Node x = root;
while (x != null) {
if (!isRed(x))
black++;
x = x.left;
}
return isBalanced(root, black);
}
// does every path from the root to a leaf have the given number of black links?
private boolean isBalanced(Node x, int black) {
if (x == null)
return black == 0;
if (!isRed(x))
black--;
return isBalanced(x.left, black) && isBalanced(x.right, black);
}
/**
* Unit tests the {@code RedBlackBST} data type.
*
* @param args
* the command-line arguments
*/
public static void main(String[] args) {
RedBlackBST<String, Integer> st = new RedBlackBST<String, Integer>();
for (int i = 0; !StdIn.isEmpty(); i++) {
String key = StdIn.readString();
st.put(key, i);
}
for (String s : st.keys())
StdOut.println(s + " " + st.get(s));
StdOut.println();
}
}
class Queue<Item> implements Iterable<Item> {
private Node<Item> first; // beginning of queue
private Node<Item> last; // end of queue
private int n; // number of elements on queue
// helper linked list class
private static class Node<Item> {
private Item item;
private Node<Item> next;
}
/**
* Initializes an empty queue.
*/
public Queue() {
first = null;
last = null;
n = 0;
}
/**
* Returns true if this queue is empty.
*
* @return {@code true} if this queue is empty; {@code false} otherwise
*/
public boolean isEmpty() {
return first == null;
}
/**
* Returns the number of items in this queue.
*
* @return the number of items in this queue
*/
public int size() {
return n;
}
/**
* Returns the item least recently added to this queue.
*
* @return the item least recently added to this queue
* @throws NoSuchElementException
* if this queue is empty
*/
public Item peek() {
if (isEmpty())
throw new NoSuchElementException("Queue underflow");
return first.item;
}
/**
* Adds the item to this queue.
*
* @param item
* the item to add
*/
public void enqueue(Item item) {
Node<Item> oldlast = last;
last = new Node<Item>();
last.item = item;
last.next = null;
if (isEmpty())
first = last;
else
oldlast.next = last;
n++;
}
/**
* Removes and returns the item on this queue that was least recently added.
*
* @return the item on this queue that was least recently added
* @throws NoSuchElementException
* if this queue is empty
*/
public Item dequeue() {
if (isEmpty())
throw new NoSuchElementException("Queue underflow");
Item item = first.item;
first = first.next;
n--;
if (isEmpty())
last = null; // to avoid loitering
return item;
}
/**
* Returns a string representation of this queue.
*
* @return the sequence of items in FIFO order, separated by spaces
*/
public String toString() {
StringBuilder s = new StringBuilder();
for (Item item : this) {
s.append(item);
s.append(' ');
}
return s.toString();
}
/**
* Returns an iterator that iterates over the items in this queue in FIFO order.
*
* @return an iterator that iterates over the items in this queue in FIFO order
*/
public Iterator<Item> iterator() {
return new ListIterator<Item>(first);
}
// an iterator, doesn't implement remove() since it's optional
private class ListIterator<Item> implements Iterator<Item> {
private Node<Item> current;
public ListIterator(Node<Item> first) {
current = first;
}
public boolean hasNext() {
return current != null;
}
public void remove() {
throw new UnsupportedOperationException();
}
public Item next() {
if (!hasNext())
throw new NoSuchElementException();
Item item = current.item;
current = current.next;
return item;
}
}
/**
* Unit tests the {@code Queue} data type.
*
* @param args
* the command-line arguments
*/
public static void main(String[] args) {
Queue<String> queue = new Queue<String>();
while (!StdIn.isEmpty()) {
String item = StdIn.readString();
if (!item.equals("-"))
queue.enqueue(item);
else if (!queue.isEmpty())
StdOut.print(queue.dequeue() + " ");
}
StdOut.println("(" + queue.size() + " left on queue)");
}
}
final class StdOut {
// force Unicode UTF-8 encoding; otherwise it's system dependent
private static final String CHARSET_NAME = "UTF-8";
// assume language = English, country = US for consistency with StdIn
private static final Locale LOCALE = Locale.US;
// send output here
private static PrintWriter out;
// this is called before invoking any methods
static {
try {
out = new PrintWriter(new OutputStreamWriter(System.out, CHARSET_NAME), true);
} catch (UnsupportedEncodingException e) {
System.out.println(e);
}
}
// don't instantiate
private StdOut() {
}
/**
* Closes standard output.
*/
public static void close() {
out.close();
}
/**
* Terminates the current line by printing the line-separator string.
*/
public static void println() {
out.println();
}
/**
* Prints an object to this output stream and then terminates the line.
*
* @param x
* the object to print
*/
public static void println(Object x) {
out.println(x);
}
/**
* Prints a boolean to standard output and then terminates the line.
*
* @param x
* the boolean to print
*/
public static void println(boolean x) {
out.println(x);
}
/**
* Prints a character to standard output and then terminates the line.
*
* @param x
* the character to print
*/
public static void println(char x) {
out.println(x);
}
/**
* Prints a double to standard output and then terminates the line.
*
* @param x
* the double to print
*/
public static void println(double x) {
out.println(x);
}
/**
* Prints an integer to standard output and then terminates the line.
*
* @param x
* the integer to print
*/
public static void println(float x) {
out.println(x);
}
/**
* Prints an integer to standard output and then terminates the line.
*
* @param x
* the integer to print
*/
public static void println(int x) {
out.println(x);
}
/**
* Prints a long to standard output and then terminates the line.
*
* @param x
* the long to print
*/
public static void println(long x) {
out.println(x);
}
/**
* Prints a short integer to standard output and then terminates the line.
*
* @param x
* the short to print
*/
public static void println(short x) {
out.println(x);
}
/**
* Prints a byte to standard output and then terminates the line.
* <p>
* To write binary data, see {@link BinaryStdOut}.
*
* @param x
* the byte to print
*/
public static void println(byte x) {
out.println(x);
}
/**
* Flushes standard output.
*/
public static void print() {
out.flush();
}
/**
* Prints an object to standard output and flushes standard output.
*
* @param x
* the object to print
*/
public static void print(Object x) {
out.print(x);
out.flush();
}
/**
* Prints a boolean to standard output and flushes standard output.
*
* @param x
* the boolean to print
*/
public static void print(boolean x) {
out.print(x);
out.flush();
}
/**
* Prints a character to standard output and flushes standard output.
*
* @param x
* the character to print
*/
public static void print(char x) {
out.print(x);
out.flush();
}
/**
* Prints a double to standard output and flushes standard output.
*
* @param x
* the double to print
*/
public static void print(double x) {
out.print(x);
out.flush();
}
/**
* Prints a float to standard output and flushes standard output.
*
* @param x
* the float to print
*/
public static void print(float x) {
out.print(x);
out.flush();
}
/**
* Prints an integer to standard output and flushes standard output.
*
* @param x
* the integer to print
*/
public static void print(int x) {
out.print(x);
out.flush();
}
/**
* Prints a long integer to standard output and flushes standard output.
*
* @param x
* the long integer to print
*/
public static void print(long x) {
out.print(x);
out.flush();
}
/**
* Prints a short integer to standard output and flushes standard output.
*
* @param x
* the short integer to print
*/
public static void print(short x) {
out.print(x);
out.flush();
}
/**
* Prints a byte to standard output and flushes standard output.
*
* @param x
* the byte to print
*/
public static void print(byte x) {
out.print(x);
out.flush();
}
/**
* Prints a formatted string to standard output, using the specified format
* string and arguments, and then flushes standard output.
*
*
* @param format
* the <a href =
* "http://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html#syntax">format
* string</a>
* @param args
* the arguments accompanying the format string
*/
public static void printf(String format, Object... args) {
out.printf(LOCALE, format, args);
out.flush();
}
/**
* Prints a formatted string to standard output, using the locale and the
* specified format string and arguments; then flushes standard output.
*
* @param locale
* the locale
* @param format
* the <a href =
* "http://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html#syntax">format
* string</a>
* @param args
* the arguments accompanying the format string
*/
public static void printf(Locale locale, String format, Object... args) {
out.printf(locale, format, args);
out.flush();
}
/**
* Unit tests some of the methods in {@code StdOut}.
*
* @param args
* the command-line arguments
*/
public static void main(String[] args) {
// write to stdout
StdOut.println("Test");
StdOut.println(17);
StdOut.println(true);
StdOut.printf("%.6f\n", 1.0 / 7.0);
}
}
final class StdIn {
/*** begin: section (1 of 2) of code duplicated from In to StdIn. */
// assume Unicode UTF-8 encoding
private static final String CHARSET_NAME = "UTF-8";
// assume language = English, country = US for consistency with System.out.
private static final Locale LOCALE = Locale.US;
// the default token separator; we maintain the invariant that this value
// is held by the scanner's delimiter between calls
private static final Pattern WHITESPACE_PATTERN = Pattern.compile("\\p{javaWhitespace}+");
// makes whitespace significant
private static final Pattern EMPTY_PATTERN = Pattern.compile("");
// used to read the entire input
private static final Pattern EVERYTHING_PATTERN = Pattern.compile("\\A");
/*** end: section (1 of 2) of code duplicated from In to StdIn. */
private static Scanner scanner;
// it doesn't make sense to instantiate this class
private StdIn() {
}
//// begin: section (2 of 2) of code duplicated from In to StdIn,
//// with all methods changed from "public" to "public static"
/**
* Returns true if standard input is empty (except possibly for whitespace). Use
* this method to know whether the next call to {@link #readString()},
* {@link #readDouble()}, etc will succeed.
*
* @return {@code true} if standard input is empty (except possibly for
* whitespace); {@code false} otherwise
*/
public static boolean isEmpty() {
return !scanner.hasNext();
}
/**
* Returns true if standard input has a next line. Use this method to know
* whether the next call to {@link #readLine()} will succeed. This method is
* functionally equivalent to {@link #hasNextChar()}.
*
* @return {@code true} if standard input has more input (including whitespace);
* {@code false} otherwise
*/
public static boolean hasNextLine() {
return scanner.hasNextLine();
}
/**
* Returns true if standard input has more input (including whitespace). Use
* this method to know whether the next call to {@link #readChar()} will
* succeed. This method is functionally equivalent to {@link #hasNextLine()}.
*
* @return {@code true} if standard input has more input (including whitespace);
* {@code false} otherwise
*/
public static boolean hasNextChar() {
scanner.useDelimiter(EMPTY_PATTERN);
boolean result = scanner.hasNext();
scanner.useDelimiter(WHITESPACE_PATTERN);
return result;
}
/**
* Reads and returns the next line, excluding the line separator if present.
*
* @return the next line, excluding the line separator if present; {@code null}
* if no such line
*/
public static String readLine() {
String line;
try {
line = scanner.nextLine();
} catch (NoSuchElementException e) {
line = null;
}
return line;
}
/**
* Reads and returns the next character.
*
* @return the next {@code char}
* @throws NoSuchElementException
* if standard input is empty
*/
public static char readChar() {
try {
scanner.useDelimiter(EMPTY_PATTERN);
String ch = scanner.next();
assert ch.length() == 1 : "Internal (Std)In.readChar() error!" + " Please contact the authors.";
scanner.useDelimiter(WHITESPACE_PATTERN);
return ch.charAt(0);
} catch (NoSuchElementException e) {
throw new NoSuchElementException(
"attempts to read a 'char' value from standard input, but there are no more tokens available");
}
}
/**
* Reads and returns the remainder of the input, as a string.
*
* @return the remainder of the input, as a string
* @throws NoSuchElementException
* if standard input is empty
*/
public static String readAll() {
if (!scanner.hasNextLine())
return "";
String result = scanner.useDelimiter(EVERYTHING_PATTERN).next();
// not that important to reset delimeter, since now scanner is empty
scanner.useDelimiter(WHITESPACE_PATTERN); // but let's do it anyway
return result;
}
/**
* Reads the next token and returns the {@code String}.
*
* @return the next {@code String}
* @throws NoSuchElementException
* if standard input is empty
*/
public static String readString() {
try {
return scanner.next();
} catch (NoSuchElementException e) {
throw new NoSuchElementException(
"attempts to read a 'String' value from standard input, but there are no more tokens available");
}
}
/**
* Reads the next token from standard input, parses it as an integer, and
* returns the integer.
*
* @return the next integer on standard input
* @throws NoSuchElementException
* if standard input is empty
* @throws InputMismatchException
* if the next token cannot be parsed as an {@code int}
*/
public static int readInt() {
try {
return scanner.nextInt();
} catch (InputMismatchException e) {
String token = scanner.next();
throw new InputMismatchException(
"attempts to read an 'int' value from standard input, but the next token is \"" + token + "\"");
} catch (NoSuchElementException e) {
throw new NoSuchElementException(
"attemps to read an 'int' value from standard input, but there are no more tokens available");
}
}
/**
* Reads the next token from standard input, parses it as a double, and returns
* the double.
*
* @return the next double on standard input
* @throws NoSuchElementException
* if standard input is empty
* @throws InputMismatchException
* if the next token cannot be parsed as a {@code double}
*/
public static double readDouble() {
try {
return scanner.nextDouble();
} catch (InputMismatchException e) {
String token = scanner.next();
throw new InputMismatchException(
"attempts to read a 'double' value from standard input, but the next token is \"" + token + "\"");
} catch (NoSuchElementException e) {
throw new NoSuchElementException(
"attempts to read a 'double' value from standard input, but there are no more tokens available");
}
}
/**
* Reads the next token from standard input, parses it as a float, and returns
* the float.
*
* @return the next float on standard input
* @throws NoSuchElementException
* if standard input is empty
* @throws InputMismatchException
* if the next token cannot be parsed as a {@code float}
*/
public static float readFloat() {
try {
return scanner.nextFloat();
} catch (InputMismatchException e) {
String token = scanner.next();
throw new InputMismatchException(
"attempts to read a 'float' value from standard input, but the next token is \"" + token + "\"");
} catch (NoSuchElementException e) {
throw new NoSuchElementException(
"attempts to read a 'float' value from standard input, but there are no more tokens available");
}
}
/**
* Reads the next token from standard input, parses it as a long integer, and
* returns the long integer.
*
* @return the next long integer on standard input
* @throws NoSuchElementException
* if standard input is empty
* @throws InputMismatchException
* if the next token cannot be parsed as a {@code long}
*/
public static long readLong() {
try {
return scanner.nextLong();
} catch (InputMismatchException e) {
String token = scanner.next();
throw new InputMismatchException(
"attempts to read a 'long' value from standard input, but the next token is \"" + token + "\"");
} catch (NoSuchElementException e) {
throw new NoSuchElementException(
"attempts to read a 'long' value from standard input, but there are no more tokens available");
}
}
/**
* Reads the next token from standard input, parses it as a short integer, and
* returns the short integer.
*
* @return the next short integer on standard input
* @throws NoSuchElementException
* if standard input is empty
* @throws InputMismatchException
* if the next token cannot be parsed as a {@code short}
*/
public static short readShort() {
try {
return scanner.nextShort();
} catch (InputMismatchException e) {
String token = scanner.next();
throw new InputMismatchException(
"attempts to read a 'short' value from standard input, but the next token is \"" + token + "\"");
} catch (NoSuchElementException e) {
throw new NoSuchElementException(
"attempts to read a 'short' value from standard input, but there are no more tokens available");
}
}
/**
* Reads the next token from standard input, parses it as a byte, and returns
* the byte.
*
* @return the next byte on standard input
* @throws NoSuchElementException
* if standard input is empty
* @throws InputMismatchException
* if the next token cannot be parsed as a {@code byte}
*/
public static byte readByte() {
try {
return scanner.nextByte();
} catch (InputMismatchException e) {
String token = scanner.next();
throw new InputMismatchException(
"attempts to read a 'byte' value from standard input, but the next token is \"" + token + "\"");
} catch (NoSuchElementException e) {
throw new NoSuchElementException(
"attempts to read a 'byte' value from standard input, but there are no more tokens available");
}
}
/**
* Reads the next token from standard input, parses it as a boolean, and returns
* the boolean.
*
* @return the next boolean on standard input
* @throws NoSuchElementException
* if standard input is empty
* @throws InputMismatchException
* if the next token cannot be parsed as a {@code boolean}:
* {@code true} or {@code 1} for true, and {@code false} or
* {@code 0} for false, ignoring case
*/
public static boolean readBoolean() {
try {
String token = readString();
if ("true".equalsIgnoreCase(token))
return true;
if ("false".equalsIgnoreCase(token))
return false;
if ("1".equals(token))
return true;
if ("0".equals(token))
return false;
throw new InputMismatchException(
"attempts to read a 'boolean' value from standard input, but the next token is \"" + token + "\"");
} catch (NoSuchElementException e) {
throw new NoSuchElementException(
"attempts to read a 'boolean' value from standard input, but there are no more tokens available");
}
}
/**
* Reads all remaining tokens from standard input and returns them as an array
* of strings.
*
* @return all remaining tokens on standard input, as an array of strings
*/
public static String[] readAllStrings() {
// we could use readAll.trim().split(), but that's not consistent
// because trim() uses characters 0x00..0x20 as whitespace
String[] tokens = WHITESPACE_PATTERN.split(readAll());
if (tokens.length == 0 || tokens[0].length() > 0)
return tokens;
// don't include first token if it is leading whitespace
String[] decapitokens = new String[tokens.length - 1];
for (int i = 0; i < tokens.length - 1; i++)
decapitokens[i] = tokens[i + 1];
return decapitokens;
}
/**
* Reads all remaining lines from standard input and returns them as an array of
* strings.
*
* @return all remaining lines on standard input, as an array of strings
*/
public static String[] readAllLines() {
ArrayList<String> lines = new ArrayList<String>();
while (hasNextLine()) {
lines.add(readLine());
}
return lines.toArray(new String[lines.size()]);
}
/**
* Reads all remaining tokens from standard input, parses them as integers, and
* returns them as an array of integers.
*
* @return all remaining integers on standard input, as an array
* @throws InputMismatchException
* if any token cannot be parsed as an {@code int}
*/
public static int[] readAllInts() {
String[] fields = readAllStrings();
int[] vals = new int[fields.length];
for (int i = 0; i < fields.length; i++)
vals[i] = Integer.parseInt(fields[i]);
return vals;
}
/**
* Reads all remaining tokens from standard input, parses them as longs, and
* returns them as an array of longs.
*
* @return all remaining longs on standard input, as an array
* @throws InputMismatchException
* if any token cannot be parsed as a {@code long}
*/
public static long[] readAllLongs() {
String[] fields = readAllStrings();
long[] vals = new long[fields.length];
for (int i = 0; i < fields.length; i++)
vals[i] = Long.parseLong(fields[i]);
return vals;
}
/**
* Reads all remaining tokens from standard input, parses them as doubles, and
* returns them as an array of doubles.
*
* @return all remaining doubles on standard input, as an array
* @throws InputMismatchException
* if any token cannot be parsed as a {@code double}
*/
public static double[] readAllDoubles() {
String[] fields = readAllStrings();
double[] vals = new double[fields.length];
for (int i = 0; i < fields.length; i++)
vals[i] = Double.parseDouble(fields[i]);
return vals;
}
//// end: section (2 of 2) of code duplicated from In to StdIn
// do this once when StdIn is initialized
static {
resync();
}
/**
* If StdIn changes, use this to reinitialize the scanner.
*/
private static void resync() {
setScanner(new Scanner(new java.io.BufferedInputStream(System.in), CHARSET_NAME));
}
private static void setScanner(Scanner scanner) {
StdIn.scanner = scanner;
StdIn.scanner.useLocale(LOCALE);
}
/**
* Reads all remaining tokens, parses them as integers, and returns them as an
* array of integers.
*
* @return all remaining integers, as an array
* @throws InputMismatchException
* if any token cannot be parsed as an {@code int}
* @deprecated Replaced by {@link #readAllInts()}.
*/
@Deprecated
public static int[] readInts() {
return readAllInts();
}
/**
* Reads all remaining tokens, parses them as doubles, and returns them as an
* array of doubles.
*
* @return all remaining doubles, as an array
* @throws InputMismatchException
* if any token cannot be parsed as a {@code double}
* @deprecated Replaced by {@link #readAllDoubles()}.
*/
@Deprecated
public static double[] readDoubles() {
return readAllDoubles();
}
/**
* Reads all remaining tokens and returns them as an array of strings.
*
* @return all remaining tokens, as an array of strings
* @deprecated Replaced by {@link #readAllStrings()}.
*/
@Deprecated
public static String[] readStrings() {
return readAllStrings();
}
/**
* Interactive test of basic functionality.
*
* @param args
* the command-line arguments
*/
public static void main(String[] args) {
StdOut.print("Type a string: ");
String s = StdIn.readString();
StdOut.println("Your string was: " + s);
StdOut.println();
StdOut.print("Type an int: ");
int a = StdIn.readInt();
StdOut.println("Your int was: " + a);
StdOut.println();
StdOut.print("Type a boolean: ");
boolean b = StdIn.readBoolean();
StdOut.println("Your boolean was: " + b);
StdOut.println();
StdOut.print("Type a double: ");
double c = StdIn.readDouble();
StdOut.println("Your double was: " + c);
StdOut.println();
}
}