提交记录 22494
用户 |
题目 |
状态 |
得分 |
用时 |
内存 |
语言 |
代码长度 |
czxb2 |
test. 自定义测试 |
Accepted |
100 |
333.478 ms |
40 KB |
C++17 |
1.67 KB |
提交时间 |
评测时间 |
2024-09-13 09:00:31 |
2024-09-13 09:00:34 |
#include <bits/stdc++.h>
using namespace std;
using u64 = uint64_t;
using u32 = uint32_t;
using ll = long long;
struct Montgomery {
u32 m, mx2, m_inv;
u64 r2;
static pair<ll, ll> exgcd(u64 a, u64 b) {
if (!b) return {1, 0};
auto [x, y] = exgcd(b, a % b);
return {y, x - a / b * y};
}
Montgomery(u32 _m = 1) {
assert(_m && _m < (1 << 30));
const u64 r = 1ull << 32;
m = _m;
mx2 = m * 2;
m_inv = -exgcd(m, r).first;
r2 = ((r % m) << 32) % m;
}
u64 reduce(u64 x) {
return (x + u32(u32(x) * m_inv) * u64(m)) >> 32;
}
u32 transform(u32 x) {
return reduce(u64(x) * r2);
}
u32 chk(u32 x) {
return x < mx2 ? x : x - mx2;
}
u32 output(u64 x) {
x = reduce(x);
if (x >= mx2) x -= mx2;
if (x >= m) x -= m;
return x;
}
};
u64 myclock() { return chrono::steady_clock::now().time_since_epoch().count(); }
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
int main() {
u64 tmp = 0 * rng();
u32 m = 998244353 ^ tmp;
m ^= tmp;
if (0)
{
u64 t = myclock();
Montgomery mod(m);
u64 one = mod.transform(1), x = 0, ans = one;
for (int i = 1; i <= 100000000; i++) {
x = mod.chk(x + one);
ans = mod.reduce(ans * x);
}
cout << mod.output(ans) << "\n";
cout << myclock() - t << "\n";
}
else
{
u64 t = myclock();
u64 ans = 1;
for (int i = 1; i <= 100000000; i++)
ans = ans * i % m;
cout << ans << "\n";
cout << myclock() - t << "\n";
}
return 0;
}
Compilation | N/A | N/A | Compile OK | Score: N/A | 显示更多 |
Testcase #1 | 333.478 ms | 40 KB | Accepted | Score: 100 | 显示更多 |
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