Minimum Size Subarray Sum
Module 11 · Sliding Window
Problem
Given a positive-integer array nums and a target, return the
length of the shortest contiguous subarray whose sum is ≥ target,
or 0 if none exists.
Examples
Example 1
Input
target = 7, nums = [2,3,1,2,4,3]Output2Explanation. [4,3], sum 7
Example 2
Input
target = 4, nums = [1,4,4]Output1Explanation. [4]
Example 3
Input
target = 11, nums = [1,1,1,1,1,1,1,1]Output0Explanation. max possible sum is 8
Constraints
1 ≤ n ≤ 10⁵ · 1 ≤ target ≤ 10⁹ · all values positive.
Attempt it first
This is the dynamic-windows lesson's opening trace, made concrete. The window's size is now the unknown — you're hunting for the shortest window meeting a lower-bound condition, which is exactly the "shrink while valid, record the smallest" template. Notice which constraint makes the whole technique legal before you write a line.