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  1. Prepare
  2. Algorithms
  3. Implementation
  4. Circular Array Rotation
  5. Discussions

Circular Array Rotation

  • piyush121
     + 90 comments

    Easy and fast as hell --> O(n) time and O(1) Space........

    public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    int N = in.nextInt();
    int K = in.nextInt();
    int Q = in.nextInt();
    int rot = K % N;
    int[] arr = new int[N];
    for (int i = 0; i < N; i++)
        arr[i] = in.nextInt();
    for (int i = 0; i < Q; i++) {
        int idx = in.nextInt();
        if (idx - rot >= 0)
            System.out.println(arr[idx - rot]);
        else
            System.out.println(arr[idx - rot + arr.length]);
		}
	}

    Thanks for the votes guys. I never thought my solution would be on the top of the discussion forums. Anyways here is the mod based solution which many people found useful. Godspeed!

    public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    int n = in.nextInt();
    int k = in.nextInt();
    int q = in.nextInt();
    int[] a = new int[n];
    for(int a_i=0; a_i < n; a_i++){
        a[a_i] = in.nextInt();
    }
    for(int a0 = 0; a0 < q; a0++){
        int m = in.nextInt();
        System.out.println(a[(n - (k % n)+ m) % n]);
    }               
}