ConcatenationOfArray.java

/*
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]

Link: [https://leetcode.com/problems/concatenation-of-array/description/]
*/

class Solution {
    public int[] getConcatenation(int[] nums) {
        int[] newArray = new int[2 * nums.length];
        
        int j = 0;

        for(int i = 0; i < 2 * nums.length; i++){
            newArray[i] = nums [j]; j++;
            if(j == nums.length) j = 0;
        }

        return newArray;
    }
}