QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#185120 | #6736. Alice and Bob | Ayouzi | AC ✓ | 106ms | 81724kb | C++14 | 2.3kb | 2023-09-21 17:24:44 | 2023-09-21 17:24:44 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 1e7 + 10, Mod = 998244353;
int Norm(int x) {
if (x < 0) x += Mod;
if (x >= Mod) x -= Mod;
return x;
}
template<class T>
T qmi(T a, ll b) {
T res = 1;
while (b) {
if (b & 1) res *= a;
b >>= 1;
a *= a;
}
return res;
}
struct Z {
int x;
Z(int x = 0) : x(Norm(x)) {}
Z(ll x) : x(Norm(x % Mod)) {}
int val() const {
return x;
}
Z operator-() const {
return Z(Norm(Mod - x));
}
Z inv() const {
assert(x != 0);
return qmi(*this, Mod - 2);
}
Z &operator*=(const Z &rhs) {
x = ll(x) * rhs.x % Mod;
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();
}
};
Z fact[N], infact[N];
void init() {
fact[0] = 1;
for (int i = 1; i < N; i ++ ) {
fact[i] = fact[i - 1] * i;
}
infact[N - 1] = 1 / fact[N - 1];
for (int i = N - 1; i; i -- ) {
infact[i - 1] = infact[i] * i;
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
init();
int n;
cin >> n;
Z ans = 0;
for (int i = 1; n - i >= i - 1; i ++ ) {
ans += fact[n - i] * fact[n - i] * infact[n - i - (i - 1)];
}
cout << ans << '\n';
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 88ms
memory: 81564kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 87ms
memory: 81644kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 87ms
memory: 81724kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 83ms
memory: 81496kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 83ms
memory: 81580kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 79ms
memory: 81556kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 83ms
memory: 81684kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 87ms
memory: 81508kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 80ms
memory: 81560kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 82ms
memory: 81548kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 83ms
memory: 81556kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 91ms
memory: 81556kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 87ms
memory: 81552kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 90ms
memory: 81560kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 106ms
memory: 81664kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 95ms
memory: 81664kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 96ms
memory: 81552kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 91ms
memory: 81680kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 95ms
memory: 81664kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 95ms
memory: 81496kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 102ms
memory: 81568kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 106ms
memory: 81496kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 99ms
memory: 81564kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"