Minimum Window Size for Sum

Given an array of positive integers `arr` and a target sum `target`, find the length of the smallest contiguous subarray that has a sum greater than or equal to `target`. If no such subarray exists, return `0`. Input Format: - The first line contains space-separated integers representing the array `arr` (1 <= |arr| <= 10000, 1 <= arr[i] <= 10000). - The second line contains an integer `target` (1 <= target <= 10^9). Output Format: - Print an integer representing the minimum length of the subarray with a sum >= target, or `0` if no such subarray exists. Example: Input: 2 3 1 2 4 3 7 Output: 2 (The smallest subarray with a sum >= 7 is [4,3].)