[Leetcode] 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.

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More practice:

If you have figured out the O(n) solution, try coding another solution using the divide and conquer approach, which is more subtle.

比较简单的DP题目，我们全程保持最优解以及以当前元素结尾的连续子数组的最大和。

    public int maxSubArray(int[] A) {
        int n = A.length;
        int max = A[0], result = A[0];
        for(int i = 1; i < n; i++) {
            max = Math.max(A[i] + max, A[i]);
            result = Math.max(max, result);
        }
        return result;
    }

这道题还有一种变种，这里是只寻找一个连续的子数组，变种是让你寻找m个连续的子数组，求解使得其和最大，这个问题的解法我稍后再补上。