Left Rotation

[문제출저][source]

문제

A left rotation operation on an array of size shifts each of the array’s elements unit to the left. For example, if left rotations are performed on array , then the array would become .

Given an array of integers and a number, , perform left rotations on the array. Then print the updated array as a single line of space-separated integers.

Input Format

The first line contains two space-separated integers denoting the respective values of (the number of integers) and (the number of left rotations you must perform). The second line contains space-separated integers describing the respective elements of the array’s initial state.

Constraints

Output Format

Print a single line of space-separated integers denoting the final state of the array after performing left rotations.

Sample Input

5 4
1 2 3 4 5
Sample Output

5 1 2 3 4
Explanation

When we perform left rotations, the array undergoes the following sequence of changes:

Thus, we print the array’s final state as a single line of space-separated values, which is 5 1 2 3 4.

풀이코드

  • 조회한 배열원소의 개수를 체크하는 cnt변수를 가지고, cnt개수가 n이 될때까지 순회.
  • d만큼 왼쪽으로 회전시킨다는것은 d만큼 시작위치를 이동시킨 후 순차적으로 배열을 순회하면 된다. 이때 인덱스의 범위가 초과되지않도록 주의해야한다.
     void rotateArray(int[] arr, int n, int d) {
        int cnt = 0, idx = d;
        while(cnt != n) {
            System.out.print(arr[idx % n] + " ");
            idx++;
            cnt++;
        }
    }

source