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.

普通版:

class Solution {    public int maxSubArray(int[] nums) {        int sum = 0;        int max = Integer.MIN_VALUE;        int len = nums.length;        for(int i = 0;i < len;i++){            if(sum < 0){                sum = nums[i];            }else{                sum += nums[i];            }            if(sum > max){                max = sum;            }        }        return max;    }}

改进版(Math.max()函数的用法很巧妙):

class Solution {    public int maxSubArray(int[] nums) {        int max = nums[0];        int sum = nums[0];        for (int i = 1; i < nums.length; i++) {            sum = Math.max(sum + nums[i], nums[i]);            max = Math.max(sum, max);        }        return max;    }}