Minimum Size Subarray Sum

Problem Statement - link #

Given an array of positive integers nums and a positive integer target, return the minimal length of a contiguous subarray [numsl, numsl+1, ..., numsr-1, numsr] of which the sum is greater than or equal to target. If there is no such subarray, return 0 instead.

Examples #

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

Constraints #

• 1 <= target <= 10^9
• 1 <= nums.length <= 10^5
• 1 <= nums[i] <= 10^5

Solutions #

class Solution {
public:
    int minSubArrayLen(int target, vector<int>& nums) {
        int l=0,s=0,len=nums.size()+1; 
        for(int i=0; i<nums.size(); i++){
            s += nums[i];
            while(s >= target){
                len = min(len, i-l+1);
                s -= nums[l++];
            }
        }
        return len > nums.size() ? 0 : len;
    }
};