QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#693928 | #6736. Alice and Bob | R73757565# | RE | 1ms | 7812kb | C++23 | 1.1kb | 2024-10-31 16:58:48 | 2024-10-31 16:58:50 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
typedef pair<int, int> PII;
typedef long long LL;
const int N = 2e5 + 10, mod = 998244353;
int q_pow(int a, int b){
int res = 1ll % mod;
while(b){
if(b & 1)res = res * a % mod;
a = a * a % mod, b>>= 1;
}
return res;
}
LL fac[N];
LL jv[N], inv[N];
void C_init(int n) {
inv[1] = 1;
for (int i = 2; i <= n; i++) {
inv[i] = (mod - mod / i) * inv[mod % i] % mod;
}
jv[0] = fac[0] = 1;
for (int i = 1; i <= n; i++) {
fac[i] = fac[i - 1] * i % mod;
jv[i] = jv[i - 1] * inv[i] % mod;
}
}
LL C(int n, int m) {
if (n < m || m < 0) return 0;
return fac[n] * jv[n - m] % mod * jv[m] % mod;
}
LL A(int n,int m){
return C(n,m)*fac[m]%mod;
}
LL lucas(int n, int m) {
if (m == 0) return 1;
return C(n % mod, m % mod) * lucas(n / mod, m / mod) % mod;
}
signed main(){
LL n;
cin >> n;
C_init(n+10);
LL ans = 0;
LL x=n-1,y=0;
while(x>=y){
ans=(ans+A(x,y)*A(x,x)%mod)%mod;
x--,y++;
}
cout<<ans<<endl;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 1ms
memory: 7724kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 5748kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 1ms
memory: 5672kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 0ms
memory: 7808kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 5680kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 0ms
memory: 5672kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 0ms
memory: 5672kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 5692kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 0ms
memory: 5764kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 7736kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5756kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 1ms
memory: 7812kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 1ms
memory: 5780kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: -100
Runtime Error
input:
1361956