Lesson 2(Iterations) - CyclicRotation

주소

app.codility.com/programmers/lessons/2-arrays/cyclic_rotation/

 

 

문제 

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.

정수로 이루어진 배열이 주어지고 배열을 옮길 회수 K가 주어집니다.

주어진 배열을 오른쪽으로 K번 이동하고 배열을 반환하는 문제입니다.

 

 

 

코드

// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int[] solution(int[] A, int K) {
        // write your code in Java SE 8

        int[] res = new int[A.length];
        
        for(int i=0; i<A.length;i++){
            res[(i+K) % A.length] = A[i];
        }

        return res;
    }
}

실제로 이동을 해서 배열을 반환하지 않고 옮기게 될 인덱스를 계산하여 결과 배열에 저장하여 반환합니다.

배열의 이동을 모듈러 연산을 통해 계산하는게 포인트입니다.

 

 

결과 

 

결과 화면입니다.

100점~