快速幂__

 a的b次方

int qmi(int a, int b) {
	int ret = 1;
	while (b) {
		if (b & 1) ret *= a;
		b >>= 1;
		a *= a;
	}
	return ret;
}

875. 快速幂 - AcWing题库

#include 
using namespace std;

typedef long long ll;
ll fun(ll a, ll b, ll k) {
	ll ret = 1;
	while (b) {
		if (b % 2 == 1) ret = (ret * a) % k;
		b >>= 1;
		a = a * a % k;
	}
	return ret;
}
int main() {
	int t;
	cin >> t;
	while (t--) {
		ll a, b, k;
		cin >> a >> b >> k;
		cout << fun(a, b, k) << endl;
	}
	return 0;
}