QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#125293 | #6736. Alice and Bob | rniya | AC ✓ | 185ms | 81252kb | C++17 | 1.7kb | 2023-07-16 14:58:49 | 2023-07-16 14:58:50 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
constexpr long long mod = 998244353;
struct mint {
long long x;
mint(long long xx = 0) : x((xx % mod + mod) % mod) {}
mint& operator+=(mint r) {
x += r.x;
if (x >= mod) x -= mod;
return *this;
}
mint& operator-=(mint r) {
if (x < r.x) x += mod;
x %= mod;
return *this;
}
mint& operator*=(mint r) {
x *= r.x;
x %= mod;
return *this;
}
mint& operator/=(mint r) {
x *= r.inv().x;
x %= mod;
return *this;
};
mint pow(long long n) {
assert(0 <= n);
mint a = *this, r = 1;
while (n) {
if (n & 1) r *= a;
a *= a;
n >>= 1;
}
return r;
}
mint inv() { return pow(mod - 2); }
friend mint operator+(mint l, mint r) { return mint(l) += r; }
friend mint operator-(mint l, mint r) { return mint(l) -= r; }
friend mint operator*(mint l, mint r) { return mint(l) *= r; }
friend mint operator/(mint l, mint r) { return mint(l) /= r; }
};
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
mint ans = 0;
vector<mint> invs(n + 1);
invs[0] = mint(0);
invs[1] = mint(1);
for (int i = 2; i <= n; i++) invs[i] = -1 * invs[mod % i] * (mod / i);
mint fac = 1, finv = 1;
for (int i = 1; i < n; i++) {
fac *= i;
finv *= invs[i];
}
for (int i = 1; n - 2 * i + 1 >= 0 and i <= n; i++) {
ans += fac * fac * finv;
fac *= invs[n - i];
finv *= n - 2 * i + 1;
finv *= n - 2 * i;
}
cout << ans.x << '\n';
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 0ms
memory: 3392kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 3424kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 0ms
memory: 3436kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 1ms
memory: 3392kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 0ms
memory: 3452kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 1ms
memory: 3436kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 1ms
memory: 3500kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 3400kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 3496kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 3460kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 0ms
memory: 3400kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 1ms
memory: 3440kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 1ms
memory: 3424kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 20ms
memory: 13820kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 128ms
memory: 62144kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 137ms
memory: 66664kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 102ms
memory: 51088kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 52ms
memory: 30420kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 110ms
memory: 57540kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 44ms
memory: 25512kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 185ms
memory: 81216kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 174ms
memory: 81236kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 172ms
memory: 81252kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"