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
nums.length - 1 (inclusive).
Input: nums = [0,2,1,5,3,4]
Explanation: The array ans is built as follows: