[Codility] arrays - CyclicRotation 풀이
예문
https://app.codility.com/programmers/lessons/2-arrays/cyclic_rotation/
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:
class Solution { public int[] solution(int[] A, int 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.
해석
- 배열 A : N개의 정수로 이루어진 배열
- 배열의 Rotation : 각 요소가 하나의 인덱스만큼 오른쪽으로 이동
- 배열의 마지막 요소에서 이동하면 제일 처음으로 이동
- 배열 A를 K번째 회전한 배열을 리턴하라!
풀이
- K번째 이동은 결국 A의 length 내에서의 이동이다.
제약사항
- N,K의 범위는 정수 [0..100]
- 배열 A의 각 요소의 범위는 정수 [−1,000..1,000]
- 정확성에 초점.
코드
public int[] solution(int[] A, int K) {
int length = A.length;
int[] result = new int[length];
for (int i = 0; i < length; i++) {
int index = (K + i) % length;
result[index] = A[i];
}
return result;
}