[LeetCode] Maximum Subarray

原题地址：https://oj.leetcode.com/problems/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.

经典的动态规划题，设 0 到 i 的连续字串最大和为sum[i]，以 i 结束的连续子串最大和为 endSum[i]，显然 sum[i] = max{endSum[i] + arr[i]，sum[i - 1]}，而 endSum[i] = max{endSum[i - 1], arr[i]}

public class Solution {    public int maxSubArray(int[] A) {        if (A == null || A.length < 1) {            return 0;        }                int endSum = Integer.MIN_VALUE;        int subSum = Integer.MIN_VALUE;                for (int i = 0; i < A.length; i++) {            // update endSum            endSum = endSum > 0 ? endSum + A[i] : A[i];            subSum = endSum > subSum ? endSum : subSum;        }                return subSum;    }}