53. Maximum Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.

For example, given the array [-2,1,-3,4,-1,2,1,-5,4],
the contiguous subarray [4,-1,2,1] has the largest sum = 6.

最大子序列和。

dp[i] = max(dp[i-1]+nums[i],nums[i]);代表以i结尾的最大和。

class Solution {
public:
    int maxSubArray(vector<int>& nums) {
        int n = nums.size();
        vector<int> dp(n);
        int Max = INT_MIN;
        dp[0] = nums[0];
        for (int i = 1; i < n; ++i) {
            int x = dp[i - 1] + nums[i];
            dp[i] = (x > nums[i]) ? x : nums[i];
        }
        for (int i = 0; i < n; ++i) {
            Max = max(Max, dp[i]);
        }
        return Max;
    }
};