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

class Solution {
public:
    vector<int> searchRange(vector<int>& nums, int target)
    {
        int n = nums.size();
        vector<int> res(2, -1);

        int left = 0, right = n;
        while (left < right) {
            int mid = left + (right - left) / 2;
            if (nums[mid] < target) {
                left = mid + 1;
            } else {
                right = mid;
            }
        }
        if (right == n || nums[right] != target) {
            return res;
        }
        res[0] = right;
        right = n;

        while (left < right) {
            int mid = left + (right - left) / 2;

            if (nums[mid] <= target) {
                left = mid + 1;
            } else {
                right = mid;
            }
        }
        res[1] = right - 1;

        return res;
    }
};

• T: $O(\log N)$
• S: $O(1)$