Find first and last occurrence in sorted array

## Problem You are given an array of integers `nums` sorted in non-decreasing order and an integer `target`. Return a pair of indices `[first, last]` such that: - `first` is the smallest index `i` with `nums[i] == target` - `last` is the largest index `j` with `nums[j] == target` If `target` does not exist in the array, return `[-1, -1]`. ## Requirements - Aim for an algorithm better than linear time (i.e., use binary search style reasoning). ## Input / Output - **Input:** `nums: int[]`, `target: int` - **Output:** `int[2]` representing `[first, last]` ## Constraints (typical) - `0 <= nums.length <= 10^5` - `nums` is sorted in non-decreasing order - Values fit in 32-bit signed integers ## Example - `nums = [5,7,7,8,8,10]`, `target = 8` → `[3,4]` - `nums = [1,2,3]`, `target = 4` → `[-1,-1]`