区间动态规划 scu2117 加分二叉树

题目链接：https://vjudge.net/problem/SCU-2117

#include <iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<map>
using namespace std;

void dfs(vector<vector<int>> &front, int i,int j)
{
    if (i > j)
        return;
    cout << front[i][j]+1 << " ";
    if (i == j)
        return;
    dfs(front, i, front[i][j] - 1);
    dfs(front, front[i][j] + 1, j);
}

int main()
{
    int n;
    int score[30];
    while (cin >> n)
    {
        for (int i = 0; i < n; i++)
            cin >> score[i];
        vector<vector<int>> dp(n, vector<int>(n, 0));
        vector<vector<int>> front(n, vector<int>(n, 0));
        for (int i = 0; i < n; i++)
        {
            dp[i][i] += score[i];
            front[i][i] = i;
        }
        for (int i = 1; i < n; i++)
        {
            for (int j = 0; j + i < n; j++)
            {
                for (int k = j; k <= j + i; k++)
                {
                    if (k == j)
                    {
                        if (dp[j][j + i] < score[j] + dp[j + 1][j + i])
                        {
                            dp[j][j + i] = score[j] + dp[j + 1][j + i];
                            front[j][j + i] = k;
                        }
                    }
                    else if (k == j + i)
                    {
                        if (dp[j][j + i] < score[j + i] + dp[j][j + i - 1])
                        {
                            dp[j][j + i] = score[j + i] + dp[j][j + i - 1];
                            front[j][j + i] = k;
                        }
                    }
                    else
                    {
                        if (dp[j][j + i] < score[k] + dp[j][k - 1] * dp[k + 1][j + i])
                        {
                            dp[j][j + i] = score[k] + dp[j][k - 1] * dp[k + 1][j + i];
                            front[j][j + i] = k;
                        }
                    }
                }
            }
        }
        cout << dp[0][n - 1] << endl;
        dfs(front, 0, n - 1);
        cout << endl;
    }
    return 0;
}