专题训练之 DP

参考：

动态规划的那些套路

动态规划的那些套路2

 

1.Leetcode1186[最大子数组变形]

class Solution {
public:
    int maximumSum(vector<int>& arr) {
        int n = arr.size();
        vector<vector<int>> dp(n, vector<int>(2, 0));
        dp[0][0] = arr[0];
        int res = arr[0];
        for (int i = 1; i < n; i++) {
            dp[i][0] = max(arr[i], dp[i-1][0]+arr[i]);
            dp[i][1] = max(dp[i-1][1]+arr[i], dp[i-1][0]);
            res = max(res, max(dp[i][0], dp[i][1]));
        }
        return res;
    }
};

leetcode1186