Exponentiation

input/code.cpp: In function 'int main()':
input/code.cpp:25:20: warning: right operand of comma operator has no effect [-Wunused-value]
   25 |         cin >> a, b;
      |                    ^
input/code.cpp:8:25: warning: 'b' may be used uninitialized [-Wmaybe-uninitialized]
    8 |     long long u = modpow(x,n/2,m);
      |                   ~~~~~~^~~~~~~~~
input/code.cpp:24:16: note: 'b' was declared here
   24 |         int a, b;
      |                ^

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;

int modpow(int x, int n, int m) {
    if (n == 0) return 1%m;
    long long u = modpow(x,n/2,m);
    u = (u*u)%m;
    if (n%2 == 1) u = (u*x)%m;
    return u;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    constexpr const int MOD = 1000000007;

    ull n;
    cin >> n;

    for(ull i=0; i<n; i++){
        int a, b;
        cin >> a, b;
        cout << modpow(a, b, MOD);
    }
}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER