Exponentiation

input/code.cpp: In function 'long long unsigned int fastpow(long long unsigned int, long long unsigned int, long long unsigned int)':
input/code.cpp:19:15: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
   19 |     if (n & 1 == 1) return x * fastpow(x, n-1, mod) % mod;
      |             ~~^~~~

#include <bits/stdc++.h>

using namespace std;

#define debug(...) Debug(#__VA_ARGS__, __VA_ARGS__);
template <typename... Args>
void Debug(const char* names, Args&&... args) {
   std::cerr << names << " = ";
   ((std::cerr << args << ", "), ...) << "\b\b " << std::endl;
}
#define ll long long
#define ull unsigned long long
#define vi vector<int>

const ull MOD = 1'000'000'007;

ull fastpow(ull x, ull n, ull mod) {
    if (n == 0) return 1;
    if (n & 1 == 1) return x * fastpow(x, n-1, mod) % mod;
    ull halfpow = fastpow(x, n/2, mod) % mod;
    return halfpow*halfpow % mod;
} 

int main() {
    int n;
    cin >> n;

    vector<ull> as(n), bs(n);

    for (int i = 0; i < n; i++)
    {
        cin >> as[i];
        cin >> bs[i];
    }
    
    for (int i = 0; i < n; i++)
    {
        cout << fastpow(as[i], bs[i], MOD) << endl;
    }
    


    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED