53. 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.

连续子数组的最大和

C++(9ms):

 1 class Solution {
 2 public:
 3     int maxSubArray(vector<int>& nums) {
 4         int len = nums.size() ;
 5         if (len < 1)
 6             return 0 ;
 7         int sum = 0 ;
 8         int Max = nums[0] ;
 9         for (int i = 0 ; i < len ; i++){
10             if (sum < 0)
11                 sum = nums[i] ;
12             else
13                 sum += nums[i] ;
14             if (sum > Max)
15                 Max = sum ;
16         }
17         return Max ;
18     }
19 };

java(15ms):

 1 class Solution {
 2     public int maxSubArray(int[] nums) {
 3         if (nums.length < 1)
 4             return 0 ;
 5         int Max = nums[0] ;
 6         int sum = 0 ;
 7         for(int i = 0 ; i < nums.length ; i++){
 8             if (sum < 0){
 9                 sum = nums[i] ;
10             }else{
11                 sum += nums[i] ;
12             }
13             if (sum > Max)
14                 Max = sum ;
15         }
16         return Max ;
17     }
18 }