Leetcode problem 23 - Build Array from Permutation

Given a zero-based permutation nums (0-indexed), build an array ans of the same length where ans[i] = nums[nums[i]] for each 0 <= i < nums.length and return it.

A zero-based permutation nums is an array of distinct integers from 0 to nums.length - 1 (inclusive).

Example 1:

Input: nums = [0,2,1,5,3,4] Output: [0,1,2,4,5,3] Explanation: The array ans is built as follows: ans = [nums[nums[0]], nums[nums[1]], nums[nums[2]], nums[nums[3]], nums[nums[4]], nums[nums[5]]] = [nums[0], nums[2], nums[1], nums[5], nums[3], nums[4]] = [0,1,2,4,5,3] Example 2:

Input: nums = [5,0,1,2,3,4] Output: [4,5,0,1,2,3] Explanation: The array ans is built as follows: ans = [nums[nums[0]], nums[nums[1]], nums[nums[2]], nums[nums[3]], nums[nums[4]], nums[nums[5]]] = [nums[5], nums[0], nums[1], nums[2], nums[3], nums[4]] = [4,5,0,1,2,3]

/**
 * @param {number[]} nums
 * @return {number[]}
 */
var buildArray = function (nums) {
  let ans = [];
  for (let i = 0; i < nums.length; i++) {
    ans.push(nums[nums[i]]);
  }
  return ans;
};

The function buildArray takes an array nums as its parameter.

It initializes an empty array ans, which will store the result of the transformation.

The function uses a for loop to iterate through each element of the nums array.

Inside the loop, it applies a specific transformation to each element. It takes the value of the element at index i (i.e., nums[i]) and uses it as an index to access another element in the nums array (i.e., nums[nums[i]]).

The element at index nums[i] is then pushed into the ans array using the ans.push() method.

After iterating through all elements of the nums array, the function returns the resulting array ans, which contains the transformed elements.