Leetcode 312. Burst Balloons

题目链接

Code:

class Solution {
public:
    int maxCoins(vector<int>& nums) {
        vector<int> arr;
        arr.push_back(1);
        for(int i:nums){
            arr.push_back(i);
        }
        arr.push_back(1);
        vector<vector<int>> dp(arr.size(),vector<int>(arr.size(),-1));
        return dfs(arr,0,arr.size()-1,dp);
    }
    
    int dfs(vector<int> &arr, int left, int right, vector<vector<int>> &dp){
        if(left+1==right) return 0;
        if(dp[left][right]!=-1) return dp[left][right];    
        int res=0;
        for(int i=left+1;i<right;++i){
            res=max(res,arr[left]*arr[i]*arr[right]+dfs(arr,left,i,dp)+dfs(arr,i,right,dp));
        }
        return dp[left][right]=res;
    }
};