bdfz_2024_summer/day4/U76034/chat.cpp
2024-08-06 11:41:16 +08:00

93 lines
1.9 KiB
C++

#include <iostream>
#include <vector>
#include <map>
#include <cmath>
#define MOD 1000000007
using namespace std;
#ifdef DEBUG
#define PRINT_VALUE(v){cout<<#v<<" :"<<v<<endl;}
#define PRINT_ARRAY(arr,size){cout<<#arr<<" [";for(int i=1;i<=size;i++){cout<<arr[i]<<(i!=size?",":"]\n");}}
#endif
#ifndef DEBUG
#define PRINT_VALUE(v)
#define PRINT_ARRAY(arr,size)
#endif
typedef long long ll;
ll power(ll a, ll b, ll mod) {
ll res = 1;
while (b > 0) {
if (b % 2 == 1)
res = (res * a) % mod;
a = (a * a) % mod;
b /= 2;
}
return res;
}
map<ll, ll> prime_factorization(ll x) {
map<ll, ll> factors;
for (ll i = 2; i * i <= x; ++i) {
while (x % i == 0) {
factors[i]++;
x /= i;
}
}
if (x > 1) {
factors[x]++;
}
return factors;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int q;
cin >> q;
vector<pair<ll, ll>> queries(q);
for (int i = 0; i < q; ++i) {
cin >> queries[i].first >> queries[i].second;
}
const int MAXN = 1e6 + 5;
vector<ll> fact(2 * MAXN), invFact(2 * MAXN);
fact[0] = 1;
for (int i = 1; i < 2 * MAXN; ++i) {
fact[i] = fact[i - 1] * i % MOD;
}
invFact[2 * MAXN - 1] = power(fact[2 * MAXN - 1], MOD - 2, MOD);
for (int i = 2 * MAXN - 2; i >= 0; --i) {
invFact[i] = invFact[i + 1] * (i + 1) % MOD;
}
auto binomial = [&](ll n, ll k) {
if (n < k) return 0LL;
return fact[n] * invFact[k] % MOD * invFact[n - k] % MOD;
};
for (auto [x, n] : queries) {
if (n == 1) {
cout << (x == 1 ? 1 : 2) << '\n';
continue;
}
map<ll, ll> factors = prime_factorization(x);
ll result = 1;
for (auto [p, e] : factors) {
result = result * binomial(2 * n + e - 1, e) % MOD;
}
cout << result << '\n';
}
return 0;
}