35. Search Insert Position(Easy).js

// 35. Search Insert Position
// 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 
*/

// Approach 1: Linear Search
// Time complexity: O(n)
// Space complexity: O(1)
var searchInsert = function (nums, target) {
  for (let i = 0; i < nums.length; i++) {
    if (nums[i] >= target) {
      return i;
    }
  }
  return nums.length;
};

//----------------------------------------------------------------------
// Approach 2: Binary Search
// Time complexity: O(log n)
// Space complexity: O(1)
var searchInsert = function (nums, target) {
  let left = 0;
  let right = nums.length - 1;

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