Problem

You are given an array of integers nums. You are also given an integer original which is the first number that needs to be searched for in nums.

You then do the following steps:

If original is found in nums, multiply it by two (i.e., set original = 2 * original). Otherwise, stop the process. Repeat this process with the new number as long as you keep finding the number.

Return the final value of original.

Example 1:

Input: nums = [5,3,6,1,12], original = 3 Output: 24 Explanation:

• 3 is found in nums. 3 is multiplied by 2 to obtain 6.
• 6 is found in nums. 6 is multiplied by 2 to obtain 12.
• 12 is found in nums. 12 is multiplied by 2 to obtain 24.
• 24 is not found in nums. Thus, 24 is returned.

Example 2:

Input: nums = [2,7,9], original = 4 Output: 4 Explanation:

• 4 is not found in nums. Thus, 4 is returned.

Constraints:

1 <= nums.length <= 1000 1 <= nums[i], original <= 1000

Pre analysis

Will keep a map to check whether number exists. If exists, will multiply by 2 and check again. If not, will return the number.

Another solution

1. Recursive approach

/**
 * @param {number[]} nums
 * @param {number} original
 * @return {number}
 */
var findFinalValue = function (nums, original) {
  const max = (x) => {
    while (nums.includes(x)) {
      return max(x * 2);
    }
    return x;
  };

  return max(original);
};

1. Iterative approach

/**
 * @param {number[]} nums
 * @param {number} original
 * @return {number}
 */
var findFinalValue = function (nums, original) {
  while (nums.includes(original)) {
    original *= 2;
  }
  return original;
};