leetcode 53. Maximum Subarray

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

Example:

Input: [-2,1,-3,4,-1,2,1,-5,4],
Output: 6
Explanation: [4,-1,2,1] has the largest sum = 6.

Follow up:

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

 

用到了以前没学过的DP算法（动态规划）

class Solution {
    public int maxSubArray(int[] nums) {
        int l = nums.length;
        int[] dp = new int[l]; //dp[i]表示以包含nums[i]的(0,i)内的子集最大和。
        dp[0] = nums[0];
        int max = dp[0];
        for(int i=1; i<l; i++) {
            dp[i] = nums[i] + ((dp[i-1]>0)? dp[i-1]:0);
            max = Math.max(max,dp[i]);
        }
        return max;
    }
}