1929. Concatenation of Array

1929. Concatenation of Array

Given an integer array numsof 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

---

Code

class Solution {
    func getConcatenation(_ nums: [Int]) -> [Int] {
        var array = nums
        return array + array
    }
}

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Refactor Code

enum error: Error {
    case invalidLength
    case invalidElement
}

class Solution {
    
    func getConcatenation(_ nums: [Int]) throws -> [Int] {
        let n = nums.count
        
        guard n >= 1 && n <= 1000 else {
            throw error.invalidLength
        }
        guard nums.allSatisfy({$0 >= 1 && $0 <= 1000}) else {
            throw error.invalidElement
        }
        
        let array = nums
        return array + array
    }
}

var test = Solution()
var nums = [1,3,2,1]

do {
    let result = try test.getConcatenation(nums)
    print(result)
} catch {
    print(error)
}

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공부하는 공돌이, 공공돌입니다🐻

@sheep1sik