[SDOI2017]数字表格
[SDOI2017]数字表格
https://ac.nowcoder.com/acm/problem/20391
这题其实并不难啊,有个结论比较显然
下面推个狮子
#include <bits/stdc++.h>
using namespace std;
typedef long long LLL;
const int N = 1e6 + 10, mod = 1e9 + 7, Mod = mod - 1;
LLL prime[N], mu[N], Fib[N], phi[N], inv_Fib[N], f[N], cnt;
bool st[N];
LLL quick_pow(LLL a, int n) {
LLL res = 1;
while(n) {
if(n & 1) res = res * a % mod;
a = a * a % mod;
n >>= 1;
}
return res;
}
LLL inv(LLL a) {
return quick_pow(a, mod - 2);
}
void init() {
Fib[1] = mu[1] = f[1] = 1;
for(int i = 2; i < N; i++)
{
f[i] = 1;
Fib[i] = (Fib[i - 1] + Fib[i - 2]) % mod;
if(!st[i]) {
prime[++cnt] = i;
mu[i] = -1;
}
for(int j = 1; j <= cnt && 1ll * i * prime[j] < N; j++)
{
st[i * prime[j]] = 1;
if(i % prime[j] == 0) break;
mu[i * prime[j]] = -mu[i];
}
}
for(int i = 1; i < N; i++) inv_Fib[i] = inv(Fib[i]);
for(int i = 1; i < N; i++)
{
for(int j = i; j < N; j += i)
{
if(mu[j / i] == 1)
f[j] = f[j] * Fib[i] % mod;
else if(mu[j / i] == -1)
f[j] = f[j] * inv_Fib[i] % mod;
}
}
f[0] = 1;
for(int i = 1; i < N; i++)
f[i] = f[i] * f[i - 1] % mod;
}
int main()
{
init();
int T;
scanf("%d", &T);
while(T--)
{
int n, m;
scanf("%d %d", &n, &m);
if(n > m) swap(n, m);
LLL res = 1;
for(int l = 1, r; l <= n; l = r + 1)
{
r = min(n / (n / l), m / (m / l));
res = res * quick_pow(f[r] * inv(f[l - 1]) % mod, 1ll * (n / l) * (m / l) % Mod) % mod;
}
printf("%lld\n", res);
}
return 0;
}