Maximum Subarray

题目

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.

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.

方法

寻找和最大的子数组，时间O(n)。

    public int maxSubArray(int[] A) {
        if (A == null) {
            return 0;
        }
        int len = A.length;
        int max = A[0];
        int cur = 0;
        for (int i = 0; i < len; i++) {
            cur += A[i];
            if (max < cur) {
                max = cur;
            }
            if (cur < 0) {
                cur = 0;
            }
        }
        return max;
    }