public static int gcd(int a, int b) {
    while(b != 0) {
        int c = a;
        a = b;
        b = c % a;
    }
    return a;
}

public static void shift_array(int[] A, int n) {
    int N = A.length;
    n %= N;
    if(n < 0)
        n = N + n;
    int d = gcd(N, n);
    for(int i = 0; i < d; i++) {
        int temp = A[i];
        for(int j = i - n + N; j != i; j = (j - n + N) % N)
            A[(j + n) % N] = A[j];
        A[i + n] = temp;
    }
}