Minimum Size Subarray Sum

Given an array of positive integers and a target sum, find the minimal length of a contiguous subarray whose sum is greater than or equal to the target. Print 0 if no such subarray exists.

Example

Input: target = 7, nums = 2 3 1 2 4 3 Output: 2 (the subarray 4 3)

Approach

A variable-size window: expand right while the sum is below target; once it meets or exceeds target, shrink from the left while recording the minimum window length, then keep expanding.

Input format

Line 1: target Line 2: the array, space-separated