Find First and Last Position of Element in Sorted Array Program (Leetcode)

Find First and Last Position of Element in Sorted Array Program (Leetcode):

Given an array of integers nums sorted in ascending order, find the starting and ending position of a given target value.

If target is not found in the array, return [-1, -1].

You must write an algorithm with O(log n) runtime complexity.

Example 1:

Input: nums = [5,7,7,8,8,10], target = 8
Output: [3,4]

Example 2:

Input: nums = [5,7,7,8,8,10], target = 6
Output: [-1,-1]

Example 3:

Input: nums = [], target = 0
Output: [-1,-1]

 

Constraints:

• 0 <= nums.length <= 105
• -109 <= nums[i] <= 109
• nums is a non-decreasing array.
• -109 <= target <= 109

#check move left or not
def binarySearch(self, nums, target, check):  
        left = 0
        right = len(nums)
        
        while left < right:
            mid = (left + right) // 2
            if (nums[mid] > target or (check and target == nums[mid])):
                right = mid
            else:
                left = mid + 1
        return left
   
def searchRange(self, nums: List[int], target: int):
        left = self.binarySearch(nums, target, True)
        if left == len(nums) or nums[left] != target:
            return [-1, -1]        

        right = self.binarySearch(nums, target, False) - 1
        return [left, right]