动态规划 多边形游戏 from 王

#include<iostream>
#include<cstdio>
#include<algorithm>
//#include<limits.h>
#include<vector>
#include<set>
using namespace std;
const int N = 55;
char op[2*N];
int arr[2*N];
int dpmax[2*N][2*N];
int dpmin[2*N][2*N];
int main()
{
    int n;
    while(cin>>n)
    {
        for(int i = 0; i < n; i++)
        {
            cin>>op[i];
            op[i+n] = op[i];
            cin>>arr[i];
            arr[i+n] = arr[i];
        }

        for(int i = 0; i < 2 * n; i++)
        {
            dpmin[i][i] = arr[i];
            dpmax[i][i] = arr[i];
        }

        for(int len = 1; len < n; len++)
        {
            for(int i = 0; i + len < 2 * n; i++)
            {
                dpmin[i][i+len] = INT_MAX;
                dpmax[i][i+len] = INT_MIN;
                for(int k = i; k < i + len; k++)
                {
                    if(op[k+1] == 't')
                    {
                        dpmin[i][i+len] = min(dpmin[i][i+len], dpmin[i][k] + dpmin[k+1][i+len]);
                        dpmax[i][i+len] = max(dpmax[i][i+len], dpmax[i][k] + dpmax[k+1][i+len]);
                    }
                    else if(op[k+1] == 'x')
                    {
                        int num1 = dpmin[i][k] * dpmin[k+1][i+len];
                        int num2 = dpmin[i][k] * dpmax[k+1][i+len];
                        int num3 = dpmax[i][k] * dpmax[k+1][i+len];
                        int num4 = dpmax[i][k] * dpmin[k+1][i+len];

                        dpmin[i][i+len] = min(dpmin[i][i+len],
                                              min(min(num1,num2), min(num3,num4)) );
                        dpmax[i][i+len] = max(dpmax[i][i+len],
                                              max(max(num1,num2), max(num3,num4)) );
                    }
                }
            }
        }

        int maxv = dpmax[0][n-1];
        for(int i = 0; i < n; i++)
        {
            maxv = max(maxv, dpmax[i][i+n-1]);
        }
        cout<<maxv<<endl;
        vector<int> vec;
        for(int i = 0; i < n; i++)
        {
            if(dpmax[i][i+n-1] == maxv)
            {
                vec.push_back(i+1);
            }
        }
        for(int i = 0; i < vec.size(); i++)
        {
            cout<<vec[i];
            if( i< vec.size() - 1) cout<<" ";
            else cout<<endl;
        }
    }
    return 0;
}