[Leet Code] Search Insert Position

Leetcode: https://leetcode.com/problems/search-insert-position/

Problem:

Given a sorted array of distinct integers and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.

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

Example 1:

Input: nums = [1,3,5,6], target = 5
Output: 2

Example 2:

Input: nums = [1,3,5,6], target = 2
Output: 1

Example 3:

Input: nums = [1,3,5,6], target = 7
Output: 4

Example 4:

Input: nums = [1,3,5,6], target = 0
Output: 0

Example 5:

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

Constraints:

• 1 <= nums.length <= 104
• -104 <= nums[i] <= 104
• nums contains distinct values sorted in ascending order.
• -104 <= target <= 104

Solution:

class Solution(object):
    def searchInsert(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        high = len(nums) -1
        low = 0
        return self.binary_search(nums, target,high, low, len(nums), 0)
    
    def binary_search(self, nums, target, high, low, curr_high, curr_low):
        if high >= low:
            middle = (high + low) // 2
            if nums[middle] > target: 
                return self.binary_search(nums, target, middle - 1, low, middle, curr_low)
            elif nums[middle] < target:
                return self.binary_search(nums, target, high, middle +1, curr_high, middle)
            else:
                return middle
        else:
            return high + 1