[LeetCode/LintCode] 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 first = 0, second = 0, sum=0;
        int minLen = INT_MAX;
        while(first<nums.size())
        {
            if(sum>=s)
            {
                minLen = min(minLen, second-first);
                sum -= nums[first++];
                continue;
            }
            if(second == nums.size()) break;
            sum += nums[second++];
        }
        return minLen == INT_MAX ? 0 : minLen;
    }
};