组合数取模 Lucas
#include <cstdio> #include <cstring> #include <algorithm> using namespace std; typedef long long ll; ll mod_pow(ll x, ll n, ll p){ ll res = 1; while(n){ if(n & 1) res =res * x % p; x = x * x % p; n >>= 1; } return res; } ll comb(ll n, ll m, ll p){ if(m > n) return 0; ll ret = 1; m = min(n - m, m); for(int i = 1; i <= m; i ++){ ll a = (n + i - m) % p; ll b = i % p; ret = ret * (a * mod_pow(b, p - 2, p) % p) % p; } return ret; } ll Lucas(ll n, ll m, ll p){ if(m == 0) return 1; return comb(n % p, m % p, p) * Lucas(n / p, m / p, p) % p; } int main(){ int T; ll n, m, p; scanf("%d", &T); while(T--){ scanf("%I64d%I64d%I64d", &n, &m, &p); printf("%I64d\n", Lucas(n, m, p)); } return 0; }