Binary Search

Problem statement

Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1.

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

Example 1:

Input: nums = [-1,0,3,5,9,12], target = 9Output: 4Explanation: 9 exists in nums and its index is 4

Example 2:

Input: nums = [-1,0,3,5,9,12], target = 2Output: -1Explanation: 2 does not exist in nums so return -1

Constraints:

• 1 <= nums.length <= 104
• -104 < nums[i], target < 104
• All the integers in nums are unique.
• nums is sorted in ascending order.

My solution

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number}
 */
var search = function(nums, target) {
    let left = 0;
    let right = nums.length - 1;
    let mid;
    
    while (left < right) {
        mid = Math.floor((left + right) / 2);
        if (nums[mid] < target) {
            left = mid + 1
        } else if (nums[mid] > target) {
            right = mid - 1;
        } else {
            return mid;
        }
    }
    return nums[left] === target ? left : -1;
};