#704 - Binary Search

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Problem Description

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.

Solution

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number}
 */
var search = function(nums, target) {
  let left = 0;
  let right = nums.length - 1;

  while (left <= right) {
    const pivot = Math.floor((right + left) / 2);
    if (nums[pivot] === target) return pivot;
    if (target < nums[pivot]) right = pivot - 1;
    else left = pivot + 1;
  }

  return -1;
};