Exponentiation

input/code.cpp: In function 'long long unsigned int fastpow(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;
      |             ~~^~~~

#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) {
    if (n == 0) return 1;
    if (n & 1 == 1) return x * fastpow(x, n-1) % MOD;
    ull halfpow = fastpow(x, n/2);
    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]) << endl;
    }
    
 
 
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED