array_permutation.py

"""
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]
"""
'''
nums = [0,2,1,5,3,4]
-> get the length of array (0 indexed). in this case, it is - 5. 
-> till the length of array - get the 
-> nums[nums[0]], nums[nums[1]], nums[nums[2]], nums[nums[3]], nums[nums[4]], nums[nums[5]]
    -> nums[nums[0]] 

'''

from typing import List

class Solution:
    def buildArray(self, nums: List[int]) -> List[int]:
        result = []
        for i in range(0, len(nums)):
            result.append(nums[nums[i]])
        return result 

#another solution
'''class Solution:
    def buildArray(self, nums: List[int]) -> List[int]:
        ans = []
        for num in range(len(nums)):
            value_check = nums[num]
            ans.append(nums[value_check])
        return ans'''

sol = Solution()
nums = [5,0,1,2,3,4]
print(sol.buildArray(nums))