209. Minimum Size Subarray Sum

Given an array of n positive integers and a positive integer s, find the minimal length of a subarray of which the sum ≥ s. If there isn't one, return
0 instead.

For example, given the array 

[2,3,1,2,4,3]

 and 

s
= 7

,

the subarray 

[4,3]

 has the minimal length under the problem constraint.

click to show more practice.

快慢两个指针 总和少了第一个指针前进 反之第二个

public class Solution {
public int minSubArrayLen(int s, int[] nums) {
int sum = 0;
int i = 0;
int j = 0;
int ret = 0;
for(;i<nums.length;i++){
sum+=nums[i];
if(sum>=s){
while(sum-nums[j]>=s){
sum = sum-nums[j];
j++;
}
int t = i-j+1;
if(ret == 0)ret=t;
if(ret>t)ret = t;
}else{
continue;
}
}
return ret;
}
}