#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define QUICK_MOD 1

int walk (int n, int test, int *count)
{
    int *visited, i;

    visited = (int*) malloc(n * sizeof(int));
    visited[0] = 0;

    srand(time(NULL));

    for (i = 0; i < test; i++) {
        int need_visit, now, j;

        for (j = 1; j < n; j++)
            visited[j] = 1;
        now = 0;
        need_visit = n - 1;

        while (need_visit != 0) {
            if (rand() > RAND_MAX / 2) {
#if QUICK_MOD
                now++;
                if (now == n) now = 0;
#else
                now = (now + 1) % n;
#endif
            }
            else {
#if QUICK_MOD
                if (now == 0)
                    now = n - 1;
                else now--;
#else
                now = (now + (n-1)) % n;
#endif
            }

            need_visit -= visited[now];
            visited[now] = 0;
//            printf("%d ", now);
        }
//        printf("\n");
        count[now]++;
    }

    free(visited);
}

int main (int argc, char **argv)
{
    int *count, n, test, i;

    if (argc < 2) {
        printf("Usage: %s n test\n", argv[0]);
        return -1;
    }

    n = atoi(argv[1]);
    test = atoi(argv[2]);
    printf("n = %d, test = %d\n", n, test);

    count = (int*) malloc(n * sizeof(int));
    for (i = 0; i < n; i++) count[i] = 0;

    walk(n, test, count);

    for (i = 0; i < n; i++) {
        printf("%2d: %d\n", i, count[i]);
    }
    return 0;
}