2525. Light Switching

单点时限: 5.0 sec

内存限制: 256 MB

Farmer John tries to keep the cows sharp by letting them play with intellectual toys. One of the larger toys is the lights in the barn. Each of the $N$ $(2 \leq N \leq 100,000)$ cow stalls conveniently numbered $1\dots N$ has a colorful light above it.

At the beginning of the evening, all the lights are off. The cows control the lights with a set of N pushbutton switches that toggle the lights; pushing switch i changes the state of light i from off to on or from on to off.

The cows read and execute a list of $M$ $(1 \leq M \leq 100,000)$ operations expressed as one of two integers ${0, 1}$.

The first operation (denoted by a 0 command) includes two subsequent integers $S_i$ and $E_i$ $(1 \leq S_i \leq E_i \leq N)$ that indicate a starting switch and ending switch. They execute the operation by pushing each pushbutton from $S_i$ through $E_i$ inclusive exactly once.

The second operation (denoted by a 1 command) asks the cows to count how many lights are on in the range given by two integers $S_i$ and $E_i$ $(1 \leq S_i \leq E_i \leq N)$ which specify the inclusive range in which the cows should count the number of lights that are on.

Help FJ ensure the cows are getting the correct answer by processing the list and producing the proper counts.


  • Line $1$: Two space-separated integers: $N$ and $M$

  • Lines $2\dots M+1$: Each line represents an operation with three space-separated integers: operation, $S_i$, and $E_i$


  • Lines 1$\dots$number of queries: For each output query, print the count as an integer by itself on a single line.


4 5
0 1 2
0 2 4
1 2 3
0 2 4
1 1 4


Four lights; five commands. Here is the sequence that should be processed:
=========1 2 3 4
Init:====O O O O , O = off * = on
0 1 2 -->* * O O ,toggle lights 1 and 2
0 2 4 -->* O * *
1 2 3 -->1 ,count the number of lit lights in range 2..3
0 2 4 -->* * O O ,toggle lights 2, 3, and 4
1 1 4 -->2 ,count the number of lit lights in the range 1..4

126 人解决,158 人已尝试。

209 份提交通过,共有 587 份提交。

3.1 EMB 奖励。

创建: 15 年,2 月前.

修改: 6 年,7 月前.

最后提交: 11 月前.

来源: USACO 2008 NOV