209. Minimum Size Subarray Sum

Given an array of positive integers nums and a positive integer target, return the minimal length of a 

subarray

 whose sum is greater than or equal to target. If there is no such subarray, return 0 instead.

Example 1:

Input: target = 7, nums = [2,3,1,2,4,3]
Output: 2
Explanation: The subarray [4,3] has the minimal length under the problem constraint.

Example 2:

Input: target = 4, nums = [1,4,4]
Output: 1

Example 3:

Input: target = 11, nums = [1,1,1,1,1,1,1,1]
Output: 0

class Solution {
public:
    int minSubArrayLen(int target, vector<int>& nums) {
        int sum = 0;
        int ans = 0;
        int i = 0;
        int result = INT32_MAX;
        for(int j = 0;j < nums.size();j ++){
            sum+=nums[j];
            while(sum>= target){
                result = min(j - i + 1,result);
                sum -= nums[i];
                i++;
            }
        }
        if(result == INT32_MAX)
            return 0;
        return result;

    }
};