输入一个整型数组，数组里有正数，也有负数。求所有子数组的和的最大值

 1 public class Solution {
 2     public static void main(String[] args) {
 3         int[] arr = {1,-2,3,10,-4,7,2,-5};
 4         System.out.println(maxSub(arr));
 5     }
 6 
 7     private static int maxSub(int[] arr) {
 8 
 9         int max = 0;
10         
11         int n = arr.length;
12         int sum = 0;
13         for(int i = 0; i < n; i++) {
14             sum = sum + arr[i];
15             if(sum > max) {
16                 max = sum;
17             } else if(sum < 0) {
18                 sum = 0;
19             }
20         }
21 
22         return max;
23     }
24 }