Find first and last index of target

You are given an integer array nums sorted in non-decreasing order and an integer target.

Return a pair [left, right] where:

• left is the index of the first occurrence of target in nums
• right is the index of the last occurrence of target in nums

If target does not exist in the array, return [-1, -1].

Requirements

• Your algorithm must run in O(log n) time.

Input/Output

• Input: nums: int[] , target: int
• Output: int[2] representing [left, right]

Constraints

• 0 <= nums.length <= 1e5
• -1e9 <= nums[i], target <= 1e9
• nums is sorted in non-decreasing order.

Examples

• nums = [5,7,7,8,8,10] , target = 8 → [3,4]
• nums = [5,7,7,8,8,10] , target = 6 → [-1,-1]
• nums = [] , target = 0 → [-1,-1]