被卡 T 飞了，what should i do?

#include <bits/extc++.h>
#include <bits/stdc++.h>
using namespace std;
using namespace __gnu_pbds;
using i64 = int64_t;
i64 QPow(i64 n, i64 m, i64 k) {
    if (m == 0) return 1;
    if (m == 1) return n;
    return QPow(n * n % k, m / 2, k) * QPow(n, m % 2, k) % k;
}
int BSGS(i64 b, i64 res, i64 p) {
    i64 step = sqrt(p) + 1;
    i64 pstep = 1;
    for (i64 i = 0; i < step; ++i) pstep = pstep * b % p;
    i64 binv = QPow(b, p - 2, p);
    i64 bs = res, gs = 1;
    gp_hash_table<i64, int> bscnt;
    for (int i = 0; i < step; ++i) {
        if (!bscnt[bs]) bscnt[bs] = i + 1;
        bs = binv * bs % p;
    }
    for (int i = 0; i < step; ++i) {
        if (bscnt[gs]) return i * step + bscnt[gs] - 1;
        gs = pstep * gs % p;
    }
    return -1;
}

void pre(int n, bool *nonprime, int *prime, int *phi, int &top) {
    nonprime[1] = 1;
    phi[1] = 1;
    for (int i = 2; i <= n; i++) {
        if (not nonprime[i]) {
            prime[++top] = i;
            phi[i] = i - 1;
        }
        for (int j = 1; j <= top && i * prime[j] <= n; j++) {
            nonprime[i * prime[j]] = 1;
            if (i % prime[j])
                phi[i * prime[j]] = phi[i] * phi[prime[j]];
            else {
                phi[i * prime[j]] = phi[i] * prime[j];
                break;
            }
        }
    }
}

const int N = 2e7 + 5;

bool nonprime[N];
int prime[5000000], fi[N], top;

i64 phi(i64 n) {
    if (n < N - 5) return fi[n];
    i64 m = sqrt(n) + 1;
    i64 ans = n;
    for (int i = 2; prime[i] <= m; i++)
        if (n % prime[i] == 0) {
            ans = ans / prime[i] * (prime[i] - 1);
            while (n % prime[i] == 0) n /= prime[i];
        }
    if (n > 1) ans = ans / n * (n - 1);
    return ans;
}

i64 PowTower(i64 a, i64 b, i64 p) {
    if (p == 1) return 0;
    if (b == 0) return 1;
    return QPow(a, (PowTower(a, b - 1, phi(p))) + phi(p), p);
}

int main() {
    pre(N - 5, nonprime, prime, fi, top);
    ios::sync_with_stdio(0);
    int T;
    cin >> T;
    while (T--) {
        i64 a, n, b, p;
        cin >> a >> n >> b >> p;
        if (n == 1) cout << BSGS(a, b, p) << "\n";
        if (n == 2) {
            int m = ceil(log2(p));
            for (int i = 0; i <= m; ++i)
                if (PowTower(a, i, p) == b) {
                    cout << i << "\n";
                    break;
                } else if (i == m)
                    cout << -1 << "\n";
        }
    }
}