1243. Polygon

单点时限: 2.0 sec

内存限制: 256 MB

Polygon is a game for one player that starts on a polygon with $N$ vertices, like the one in Figure 1, where $N=4$. Each vertex is labelled with an integer and each edge is labelled with either the symbol + (addition) or the symbol * (product). The edges are numbered from $1$ to $N$.

Write a program that, given a polygon, computes the highest possible score and lists all the edges that, if removed on the first move, can lead to a game with that score.

输入格式

Your program is to read from standard input. The input describes a polygon with $N$ vertices. It contains two lines. On the first line is the number $N$. The second line contains the labels of edges $1, \ldots, N$, interleaved with the vertices’ labels (first that of the vertex between edges $1$ and $2$, then that of the vertex between edges $2$ and $3$, and so on, until that of the vertex between edges $N$ and $1$), all separated by one space. An edge label is either the letter t (representing +) or the letter x (representing *).

$3 \le N \le 50$

For any sequence of moves, vertex labels are in the range $[-32768,32767]$.

输出格式

Your program is to write to standard output. On the first line your program must write the highest score one can get for the input polygon. On the second line it must write the list of all edges that, if removed on the first move, can lead to a game with that score. Edges must be written in increasing order, separated by one space.

样例

Input
4
t -7 t 4 x 2 x 5
Output
33
1 2

4 人解决,8 人已尝试。

5 份提交通过,共有 24 份提交。

8.3 EMB 奖励。

创建: 17 年,5 月前.

修改: 6 年,9 月前.

最后提交: 1 年,4 月前.

来源: IOI 1998

题目标签