[LeetCode]#1920. Build Array from Permutation

Fatboy Slim
Jul 15, 2021

Environment: Python 3.8

Key technique: for

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]

Analysis:

  1. Use formula and[i]=nums[nums[i]]

Solution:

class Solution:
def buildArray(self, nums):
return [nums[nums[i]] for i in range(len(nums))]

Submissions:

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