[Codility] CyclicRotation

s_sangs·2022년 2월 22일
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Algorithm

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문제 설명

An array A consisting of N integers is given.
Rotation of the array means that each element is shifted right by one index,
and the last element of the array is moved to the first place.
For example, the rotation of array A = [3, 8, 9, 7, 6] is [6, 3, 8, 9, 7]
(elements are shifted right by one index and 6 is moved to the first place).

The goal is to rotate array A K times; that is, each element of A will be shifted to the right K times.

Write a function:

function solution(A, K);

that, given an array A consisting of N integers and an integer K, returns the array A rotated K times.

For example, given

    A = [3, 8, 9, 7, 6]
    K = 3
the function should return [9, 7, 6, 3, 8]. Three rotations were made:

    [3, 8, 9, 7, 6] -> [6, 3, 8, 9, 7]
    [6, 3, 8, 9, 7] -> [7, 6, 3, 8, 9]
    [7, 6, 3, 8, 9] -> [9, 7, 6, 3, 8]
For another example, given

    A = [0, 0, 0]
    K = 1
the function should return [0, 0, 0]

Given

    A = [1, 2, 3, 4]
    K = 4
the function should return [1, 2, 3, 4]

Assume that:

N and K are integers within the range [0..100];
each element of array A is an integer within the range [−1,000..1,000].
In your solution, focus on correctness.
The performance of your solution will not be the focus of the assessment.

풀이

function solution(A, K) {
  // write your code in JavaScript (Node.js 8.9.4)
  if (A.length != 0) {
    for (let i = 0; i < K; i++) {
      let tmp = A.pop();
      A.unshift(tmp);
    }
    return A;
  } else {
    return [];
  }
}

예외에 대한 처리를 잘 확인해야할 것 같다.
A 배열은 N개의 정수가 주어진다고 했는데, N의 범위는 0에서 100이다.
A가 빈 배열일 때에 대한 예외처리를 해주지 않았다.

문제 자체는 맨 뒤에 있는 배열의 원소를 맨 앞으로 보내주는 함수라서 pop()unshift()를 이용해서 간단하게 구현할 수 있었다.

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