1470

1470. Shuffle the Array (Easy)

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

Related Topics:
Array

Solution 1.

// OJ: https://leetcode.com/problems/shuffle-the-array/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(N)
class Solution {
public:
    vector<int> shuffle(vector<int>& nums, int n) {
        vector<int> a, b, ans;
        for (int i = 0; i < 2 * n; ++i) {
            if (i < n) a.push_back(nums[i]);
            else b.push_back(nums[i]);
        }
        for (int i = 0; i < n; ++i) {
            ans.push_back(a[i]);
            ans.push_back(b[i]);
        }
        return ans;
    }
};

Solution 2.

// OJ: https://leetcode.com/problems/shuffle-the-array/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(1)
class Solution {
public:
    vector<int> shuffle(vector<int>& nums, int n) {
        vector<int> ans(2 * n);
        for (int i = 0; i < 2 * n; ++i) {
            if (i < n) ans[2 * i] = nums[i];
            else ans[2 * (i - n) + 1] = nums[i];
        }
        return ans;
    }
};