mirror of
https://git.sb/baoshuo/OI-codes.git
synced 2024-11-30 18:56:26 +00:00
54 lines
954 B
C++
54 lines
954 B
C++
#include <iostream>
|
|
|
|
using std::cin;
|
|
using std::cout;
|
|
const char endl = '\n';
|
|
|
|
const int N = 5e6 + 5;
|
|
|
|
int n, p, _k, k, a[N], b[N], s[N], ans;
|
|
|
|
int binpow(int a, int b) {
|
|
int res = 1;
|
|
|
|
while (b) {
|
|
if (b & 1) res = static_cast<long long>(res) * a % p;
|
|
a = static_cast<long long>(a) * a % p;
|
|
b >>= 1;
|
|
}
|
|
|
|
return res;
|
|
}
|
|
|
|
int main() {
|
|
std::ios::sync_with_stdio(false);
|
|
cin.tie(nullptr);
|
|
|
|
cin >> n >> p >> _k;
|
|
|
|
s[0] = 1;
|
|
|
|
for (int i = 1; i <= n; i++) {
|
|
cin >> a[i];
|
|
|
|
s[i] = static_cast<long long>(s[i - 1]) * a[i] % p;
|
|
}
|
|
|
|
b[n + 1] = binpow(s[n], p - 2);
|
|
|
|
for (int i = n; i; i--) {
|
|
b[i] = static_cast<long long>(b[i + 1]) * a[i] % p;
|
|
}
|
|
|
|
k = _k;
|
|
|
|
for (int i = 1; i <= n; i++) {
|
|
ans = (ans + static_cast<long long>(s[i - 1]) * b[i + 1] % p * k) % p;
|
|
k = static_cast<long long>(k) * _k % p;
|
|
}
|
|
|
|
cout << ans << endl;
|
|
|
|
return 0;
|
|
}
|