数论-快速幂-快速乘

快速幂：求 a^b % p

#include <iostream>
using namespace std;

typedef long long LL;

LL qmi(LL a, LL b, LL p){
    LL res = 1 % p;
    while(b){
        if(b & 1)res = res * a % p;
        a = a * a % p;
        b >>= 1;
    }
    return res;
}

快速乘：a * b % p

#include <iostream>
using namespace std;

typedef long long ll;

ll qmul(ll a, ll b, ll p){
    ll res = 0;
    while(a){
        if(a&1) res = (res + b) % p;
        b = b * 2 % p;
        a >>= 1;
    }
    return res;
}

int main(){
    ll a, b, p;
    cin >> a >> b >> p;
    cout << qmul(a, b, p) << endl;
}