for(int i = 1; i <= n / 2; i++) {
        memset(vis, 0, sizeof(vis));
        path[cur] = 0;
        cur++;
        path[cur] = i;
        cur++;
        int l = i, r = i;
        vis[0] = true;
        vis[i] = true;
        for(int j = 0; j < n - 2; j++) {
            if(j % 2 == 0) {
                while(vis[l]) {
                    l--;
                    if(l < 0) l += n;
                }
                vis[l] = true;
                path[cur++] = l;
            }
            else {
                while(vis[r]) {
                    r++;
                    if(r == n) r -= n;
                }
                vis[r] = true;
                path[cur++] = r;
            }
        }
    }