ConcatenationOfArray.java

import java.util.Arrays;

/*
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]

 */
public class ConcatenationOfArray {
    public static void main(String[] args) {
        int[] nums={1,2,1};
        int[] result=getConcatenation(nums);
        System.out.println(Arrays.toString(result));
    }
    public static int[] getConcatenation(int[] nums) {
        int n = nums.length;
        int[] ans = new int[2*n];
        for(int i = 0; i<n; i++){
            ans[i]=nums[i];
            ans[i+n]=nums[i];
        }
        return ans;
    }
}