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.

一刷
题解：
初始设置结果为Integer.MIN_VALUE，然后当前curMax小于0时重置其为0。

Time Complexity - O(n)， Space Complexity - O(1)。

public class Solution {
    public int maxSubArray(int[] nums) {
        if(nums == null) return 0;
        int max=Integer.MIN_VALUE, start =0, curSum = 0;
        for(int i=0; i<nums.length; i++){
            curSum +=nums[i];
             max = Math.max(max, curSum);
           if(curSum<0) curSum = 0;
        }
        
        return max;
    }
}