Find shortest subarray with at least k distinct

## Problem Given an integer array `nums` and an integer `k`, find the length of the **shortest contiguous subarray** that contains **at least `k` distinct integers**. ### Task Return the minimum length of such a subarray. If no subarray contains at least `k` distinct integers, return `-1`. ### Input/Output - Input: `nums` (length `n`), integer `k` - Output: integer (minimum length or `-1`) ### Constraints (reasonable interview assumptions) - `1 <= n <= 2*10^5` - `1 <= k <= n` - `nums[i]` fits in 32-bit signed integer ### Examples - `nums = [1,2,1,3,4], k = 3` → answer `3` (e.g., `[2,1,3]`) - `nums = [1,1,1], k = 2` → answer `-1`