Array Binary Search
Learner Level

Implement the binarySearchPosition method that returns the index of the target using binary search.

The input contains a sorted integer array nums, its length size, and an integer target. Your task is to return the index of target using binary search.

If the target exists in the array, return its index. If it does not exist, return -1. For example, in [1,3,5,7,9], the target 7 is at index 3.

Example 1
Input:
nums (int[]) = [1,3,5,7,9]
size (int) = 5
target (int) = 7
Return:
(int) 3
Example 2
Input:
nums (int[]) = [2,4,6]
size (int) = 3
target (int) = 5
Return:
(int) -1
Example 3
Input:
nums (int[]) = [10]
size (int) = 1
target (int) = 10
Return:
(int) 0

Binary search works by repeatedly cutting the search range in half.

Keep two pointers, left and right. Check the middle element. If it is equal to the target, return the middle index. If the middle value is smaller, search the right half. Otherwise, search the left half.

Pseudocode:

function binarySearchPosition(nums, size, target):
    left = 0
    right = size - 1
    while left <= right:
        mid = left + (right - left) / 2
        if nums[mid] == target:
            return mid
        else if nums[mid] < target:
            left = mid + 1
        else:
            right = mid - 1
    return -1
Run your code to see the result.