leetcode1929.Concatenation of Array

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

Runtime: 0 ms, faster than 100.00% of Java online submissions for Concatenation of Array.

Memory Usage: 42.6 MB, less than 95.59% of Java online submissions for Concatenation of Array.

属于很简单的一道题了，没啥说的了。