uva 10515 - Powers Et Al.(数论)

#include <cstdio>
#include <cstring>
#include <vector>

using namespace std;

const int maxn = 15;
const int maxs = 105;

vector<int> g[maxn];
char a[maxs], b[maxs];

void init () {

int v[maxn];
for (int i = 0; i < maxn; i++) {

int tmp = i;
memset(v, 0, sizeof (v));

while (v[tmp] == 0) {
v[tmp] = 1;
g[i].push_back(tmp);
tmp = tmp * i % 10;
}
}
}

int main () {
init();
while (scanf("%s%s", a, b) == 2 && ( strcmp(a,"0") || strcmp(b,"0")) ) {

if (strcmp(b, "0") == 0) {
printf("1\n");
continue;
}

int u = a[strlen(a)-1] - '0';
int len = strlen(b);

int tmp = 1, m = g[u].size();
for (int i = 0; i < len; i++)
tmp = (tmp * 10 + (b[i] - '0')) % m;
printf("%d\n", g[u][(tmp-1+m)%m]);
}
return 0;
}