QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#406248 | #6736. Alice and Bob | gugg | AC ✓ | 102ms | 159908kb | C++20 | 2.7kb | 2024-05-06 23:20:26 | 2024-05-06 23:20:27 |
Judging History
answer
#include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <map>
#include <set>
#include <cmath>
#include <bitset>
#include <cassert>
#include <numeric>
using namespace std;
typedef long long ll;
constexpr int P = 998244353;
// assume -P <= x < 2P
ll norm(ll x) {
if (x < 0) {
x += P;
}
if (x >= P) {
x -= P;
}
return x;
}
template<class T>
T power(T a, int b) {
T res = 1;
for (; b; b /= 2, a *= a) {
if (b % 2) {
res *= a;
}
}
return res;
}
struct Z {
ll x;
Z(ll x = 0) : x(norm(x% P)) {}
ll val() const {
return x;
}
Z operator-() const {
return Z(norm(P - x));
}
Z inv() const {
assert(x != 0);
return power(*this, P - 2);
}
Z& operator*=(const Z& rhs) {
x = x * rhs.x % P;
return *this;
}
Z& operator+=(const Z& rhs) {
x = norm(x + rhs.x);
return *this;
}
Z& operator-=(const Z& rhs) {
x = norm(x - rhs.x);
return *this;
}
Z& operator/=(const Z& rhs) {
return *this *= rhs.inv();
}
friend Z operator*(const Z& lhs, const Z& rhs) {
Z res = lhs;
res *= rhs;
return res;
}
friend Z operator+(const Z& lhs, const Z& rhs) {
Z res = lhs;
res += rhs;
return res;
}
friend Z operator-(const Z& lhs, const Z& rhs) {
Z res = lhs;
res -= rhs;
return res;
}
friend Z operator/(const Z& lhs, const Z& rhs) {
Z res = lhs;
res /= rhs;
return res;
}
friend std::istream& operator>>(std::istream& is, Z& a) {
ll v;
is >> v;
a = Z(v);
return is;
}
friend std::ostream& operator<<(std::ostream& os, const Z& a) {
return os << a.val();
}
};
const int N = 10000010;
Z fact[N], infact[N];
void init()
{
fact[0] = infact[0] = 1;
for (int i = 1; i < N; i ++ )
fact[i] = fact[i - 1] * i;
infact[N - 1] = fact[N - 1].inv();
for (int i = N - 2; i >= 1; i --)
infact[i] = infact[i + 1] * (i + 1);
}
Z A(int a, int b)
{
return fact[a] * infact[a - b];
}
void solve()
{
int n;
cin >> n;
Z ans = 0;
for (int i = 1; i <= n; i ++)
{
if (n - i < i - 1) break;
ans += A(n - i, i - 1) * fact[n - i];
}
cout << ans << '\n';
}
int main()
{
ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
init();
int tt = 1;
// cin >> tt;
while (tt --)
{
solve();
}
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 95ms
memory: 159900kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 86ms
memory: 159868kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 93ms
memory: 159904kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 87ms
memory: 159808kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 87ms
memory: 159876kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 84ms
memory: 159768kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 91ms
memory: 159840kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 88ms
memory: 159772kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 91ms
memory: 159852kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 81ms
memory: 159812kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 93ms
memory: 159864kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 88ms
memory: 159904kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 87ms
memory: 159840kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 91ms
memory: 159868kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 102ms
memory: 159904kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 99ms
memory: 159772kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 94ms
memory: 159812kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 90ms
memory: 159840kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 100ms
memory: 159900kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 92ms
memory: 159804kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 100ms
memory: 159856kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 100ms
memory: 159908kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 94ms
memory: 159876kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"