【leetcode】53. Maximum Subarray

53. Maximum Subarray

https://leetcode.com/problems/maximum-subarray/#/description

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.

思路

subproblem：

dp[i]为以a[i]结尾的连续子序列的和，则有以下递推式

dp[i] = dp[i-1]>0?dp[i-1]+a[i]:a[i]

然后用一个max保存目前找到的最大的subarray，返回这个max

代码

public class Solution {
public int maxSubArray(int[] nums) {
if(nums.length==0)return 0;
int[] dp = new int[nums.length];//以nums
结尾的连续子序列和
dp[0] = nums[0];
int max = dp[0];
for(int i = 1;i<nums.length;i++){
dp[i] = nums[i]+(dp[i-1]>0?dp[i-1]:0);
max = Math.max(max,dp[i]);
}
return max;
}
}