QOJ.ac
QOJ
| ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
|---|---|---|---|---|---|---|---|---|---|
| #140999 | #6736. Alice and Bob | cciafrino# | AC ✓ | 160ms | 120268kb | C++20 | 2.9kb | 2023-08-17 05:12:57 | 2023-08-17 05:13:00 |
Judging History
answer
#include<bits/stdc++.h>
namespace std {
int minv(int a, int m) {
a %= m; assert(a);
return a == 1 ? 1 : int(m - int64_t(minv(m, a)) * m / a);
}
template<unsigned M_> struct modnum {
static constexpr unsigned M = M_;
using ll = int64_t; using ull = uint64_t; unsigned x;
modnum& norm(unsigned a) { x = a < M ? a : a - M; return *this; }
constexpr modnum(ll a = 0U) : x(unsigned((a %= ll(M)) < 0 ? a + ll(M) : a)) {}
explicit operator int() const { return x; }
modnum& operator+=(const modnum& a) { return norm(x + a.x); }
modnum& operator-=(const modnum& a) { return norm(x - a.x + M); }
modnum& operator*=(const modnum& a) { x = unsigned(ull(x) * a.x % M); return *this; }
modnum& operator/=(const modnum& a) { return (*this *= a.inv()); }
modnum operator+(const modnum& a) const { return (modnum(*this) += a); }
modnum operator-(const modnum& a) const { return (modnum(*this) -= a); }
modnum operator*(const modnum& a) const { return (modnum(*this) *= a); }
modnum operator/(const modnum& a) const { return (modnum(*this) /= a); }
template<typename T> friend modnum operator+(T a, const modnum& b) { return (modnum(a) += b); }
template<typename T> friend modnum operator-(T a, const modnum& b) { return (modnum(a) -= b); }
template<typename T> friend modnum operator*(T a, const modnum& b) { return (modnum(a) *= b); }
template<typename T> friend modnum operator/(T a, const modnum& b) { return (modnum(a) /= b); }
modnum operator+() const { return *this; }
modnum operator-() const { return modnum() - *this; }
modnum pow(ll e) const {
if (e < 0) return inv().pow(-e);
modnum b = x, xe = 1U;
for (; e; e >>= 1) { if (e & 1) xe *= b; b *= b; }
return xe;
}
modnum inv() const { return minv(x, M); }
friend modnum inv(const modnum& a) { return a.inv(); }
explicit operator bool() const { return x; }
friend bool operator==(const modnum& a, const modnum& b) { return a.x == b.x; }
friend bool operator!=(const modnum& a, const modnum& b) { return a.x != b.x; }
friend ostream &operator<<(ostream& os, const modnum& a) { return os << a.x; }
friend istream &operator>>(istream& in, modnum& n) { ll v_; in >> v_; n = modnum(v_); return in; }
}; }
int main() {
using namespace std;
cin.tie(nullptr)->sync_with_stdio(false);
int N; cin >> N;
using num = modnum<998244353U>;
vector<num> fact(N+1);
vector<num> ifact(N+1);
vector<num> invs(N+1);
fact[0] = ifact[0] = 1;
invs[1] = 1;
for (int x = 2; x <= N; ++x) {
invs[x] = -((num::M/x * invs[num::M % x]));
}
for (int x = 1; x <= N; ++x) {
fact[x] = fact[x-1] * x;
ifact[x] = ifact[x-1] * invs[x];
}
auto choose = [&](int n, int r) -> num {
return (0 <= r && r <= n ? fact[n] * ifact[n-r] * ifact[r] : 0);
};
num ways = 0;
for (int x = 1; x <= N; ++x) {
ways += choose(N-x, x-1) * fact[x-1] * fact[N-x];
}
cout << ways << '\n';
}
詳細信息
Test #1:
score: 100
Accepted
time: 1ms
memory: 3564kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 3480kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 0ms
memory: 3444kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 1ms
memory: 3448kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 3484kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 1ms
memory: 3508kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 1ms
memory: 3528kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 3460kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 3468kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 3468kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 3488kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 0ms
memory: 3460kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 1ms
memory: 3460kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 21ms
memory: 19152kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 119ms
memory: 91944kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 123ms
memory: 98572kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 100ms
memory: 74928kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 53ms
memory: 44452kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 107ms
memory: 84756kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 42ms
memory: 36988kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 160ms
memory: 120268kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 160ms
memory: 120232kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 152ms
memory: 120224kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"