Ultraviolet A 10515-Powers et al. (number theory)

Link: Ultraviolet A 10515-Powers et al.

Give M and N and ask the number of Mn.

Solution: in fact, you only need to look at the last digit of M, judge the period with the most digit, and then use N % T.

#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;}