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70
Luogu/P2155/P2155.cpp
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70
Luogu/P2155/P2155.cpp
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#include <iostream>
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#include <algorithm>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 1e7 + 5;
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int t, mod, p, primes[N], fac[N], fac_phi[N];
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bool not_prime[N];
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int binpow(int a, int b) {
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int res = 1;
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while (b) {
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if (b & 1) res = static_cast<long long>(res) * a % mod;
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a = static_cast<long long>(a) * a % mod;
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b >>= 1;
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}
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return res;
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}
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int main() {
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std::ios::sync_with_stdio(false);
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cin.tie(nullptr);
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cin >> t >> mod;
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for (int i = 2; i < N; i++) {
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if (!not_prime[i]) primes[++p] = i;
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for (int j = 1; j <= p && i * primes[j] < N; j++) {
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not_prime[i * primes[j]] = true;
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if (i % primes[j] == 0) break;
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}
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}
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fac[0] = 1;
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for (int i = 1; i < N; i++) {
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if (i % mod) {
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fac[i] = static_cast<long long>(fac[i - 1]) * i % mod;
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} else {
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fac[i] = fac[i - 1];
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}
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}
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fac_phi[1] = 1;
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for (int i = 2; i < N; i++) {
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if (not_prime[i]) {
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fac_phi[i] = static_cast<long long>(fac_phi[i - 1]) * i % mod;
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} else {
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fac_phi[i] = static_cast<long long>(fac_phi[i - 1]) * (i - 1) % mod;
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}
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}
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while (t--) {
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int n, m;
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cin >> n >> m;
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cout << (n / mod > m / mod ? 0 : static_cast<long long>(fac[n]) * fac_phi[m] % mod * binpow(fac[m], mod - 2) % mod) << endl;
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}
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return 0;
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}
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Luogu/P2155/data/P2155_2.in
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Luogu/P2155/data/P2155_2.in
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Luogu/P2155/data/P2155_2.out
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Luogu/P2155/data/P2155_2.out
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