1900 - 1999
1929 - Concatenation of Array (Easy)
Problem Link
https://leetcode.com/problems/concatenation-of-array/
Problem Statement
Given an integer array nums of length n, you want to create an array ans of length 2n where ans[i] == nums[i] and ans[i + n] == nums[i] for 0 <= i < n (0-indexed).
Specifically, ans is the concatenation of two nums arrays.
Return the array ans.
Example 1:
Input: nums = [1,2,1]
Output: [1,2,1,1,2,1]
Explanation: The array ans is formed as follows:
- ans = [nums[0],nums[1],nums[2],nums[0],nums[1],nums[2]]
- ans = [1,2,1,1,2,1]Example 2:
Input: nums = [1,3,2,1]
Output: [1,3,2,1,1,3,2,1]
Explanation: The array ans is formed as follows:
- ans = [nums[0],nums[1],nums[2],nums[3],nums[0],nums[1],nums[2],nums[3]]
- ans = [1,3,2,1,1,3,2,1]Constraints:
n == nums.length1 <= n <= 10001 <= nums[i] <= 1000
Approach 1: Iteration
We need to look at nums two times to create the desired result. The simplest approach is to perform two for-loops in nums and copy the numbers to result .
def getConcatenation(self, nums: List[int]) -> List[int]:
#initialize result
result = []
#first iteration of nums
for i in range(len(nums)):
result.append(nums[i])
#second iteration of nums
for i in range(len(nums)):
result.append(nums[i])
#return result
return result