UVA 350 (暑假-数论 -E - Pseudo-Random Numbers)

#include <cstdio>

int main() {
int z, i, m, l, t = 0;
while (scanf("%d%d%d%d", &z, &i, &m, &l) && (z || i || m || l)) {
int value[10001] = {0}, count = 0;
while (++count) {
l = (z *l + i) % m;
value[l]++;
if (value[l] == 2)
break;
}
printf("Case %d: %d\n", ++t, count - 1);
}
return 0;
}