Concatenation of Array

Description

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.length
• 1 <= n <= 1000
• 1 <= nums[i] <= 1000

Solution(javascript)

/**
 * @param {number[]} nums
 * @return {number[]}
 */
var getConcatenation = function(nums) {
    let concatArray = [];
    
    let numsLength = nums.length;
    
    for (let i = 0; i < numsLength; i++) {
        concatArray[i] = nums[i]
    }
        
    for (let j = 0; j < numsLength; j++) {
        concatArray[j + numsLength] = nums[j]
    }

    
    return concatArray;
  
};