uva 408(数学)

题解：将种子设为0，然后通过题目的公式算出新的种子，再次带入，直到找到种子的周期，看这个周期是不是包含了所有从0到mod - 1的所有数，如果是就是good 否则就是bad.

#include <iostream>#include <cstdio>using namespace std;int main() {int step, mod, seed, flag, n;while (scanf("%d%d", &step, &mod) != EOF) {seed = flag = n = 0;while (1) {flag++;seed = (seed + step) % mod;if (seed == n)break;}if (flag == mod)printf("%10d%10d    Good Choice\n\n", step, mod);elseprintf("%10d%10d    Bad Choice\n\n", step, mod);}return 0;}