[Leetcode]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.

class Solution {public:    int minSubArrayLen(int s, vector<int>& nums) {        int minlen = numeric_limits<int>::max();        int start = -1;        int sum = 0;        for (int i = 0; i < nums.size(); ++i) {            sum += nums[i];            while (sum >= s) {                minlen = min(minlen, i - start);                sum -= nums[++start];            }        }        if (minlen == INT_MAX)            return 0;        return minlen;    }};