34. Find First and Last Position of Element in Sorted Array

1function searchRange(nums: number[], target: number): number[] {
2    function leftSearch(nums: number[], target: number): number {
3        let left = 0, right = nums.length - 1
4        let res = -1
5        while (left <= right) {
6            const mid = left + Math.floor((right - left) / 2)
7            if (nums[mid] < target) left = mid + 1
8            else {
9                if (nums[mid] === target) res = mid;
10                right = mid - 1
11            }
12        }
13
14        return res
15    }
16
17    function rightSearch(nums: number[], target: number): number {
18        let left = 0, right = nums.length - 1
19        let res = -1
20        while (left <= right) {
21            const mid = left + Math.floor((right - left) / 2)
22            if (nums[mid] > target) right = mid - 1
23            else {
24                if (nums[mid] === target) res = mid;
25                left = mid + 1
26            }
27        }
28
29        return res
30    }
31
32    const first = leftSearch(nums, target)
33    if (first === -1) return [-1, -1]
34    const last = rightSearch(nums, target)
35    return [first, last]
36};