1470. Shuffle the Array

Given the array nums consisting of 2n elements in the form [x1,x2,...,xn,y1,y2,...,yn].

Return the array in the form [x1,y1,x2,y2,...,xn,yn].

Example 1:

Input: nums = [2,5,1,3,4,7], n = 3
Output: [2,3,5,4,1,7] 
Explanation: Since x1=2, x2=5, x3=1, y1=3, y2=4, y3=7 then the answer is [2,3,5,4,1,7].

Example 2:

Input: nums = [1,2,3,4,4,3,2,1], n = 4
Output: [1,4,2,3,3,2,4,1]

Example 3:

Input: nums = [1,1,2,2], n = 2
Output: [1,2,1,2]

Constraints:

• 1 <= n <= 500
• nums.length == 2n
• 1 <= nums[i] <= 10^3

class Solution {
    public int[] shuffle(int[] nums, int n) {
        int[] a1 = new int[n];
        int[] a2 = new int[n];
        for(int i = 0; i < 2*n; i++){
            if(i < n){
                a1[i] = nums[i];
            }
            else a2[i - n] = nums[i];
        }
        List<Integer> list = new ArrayList();
        for(int i = 0; i < n; i++){
            list.add(a1[i]);
            list.add(a2[i]);
        }
        int[] ar = new int[2*n];
        for(int i = 0; i < 2*n;i++){
            ar[i] = list.get(i);
        }
        return ar;
    }
}

class Solution {
    public int[] shuffle(int[] nums, int n) {
        int[] res = new int[2*n];
        for(int i = 0, j = 0; j < n; i += 2){
            res[i] = nums[j];
            res[i+1] = nums[j+n];
            j++;
        }
        return res;
    }
}