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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 |
---|---|---|---|---|---|---|---|---|---|
#383931 | #6736. Alice and Bob | GordenGhost# | WA | 152ms | 142344kb | C++17 | 1.3kb | 2024-04-09 18:58:28 | 2024-04-09 18:58:30 |
Judging History
answer
#include"bits/stdc++.h"
#define endl '\n'
using ll=long long;
using namespace std;
constexpr int N=10000000+5,mod=998244353;
ll fact[N],inv[N];
ll qpow(ll a,ll b,ll p){
a%=p;
ll ans=1%p;
for(;b;b>>=1){
if(b&1)
ans=ans*a%p;
a=a*a%p;
}
return ans;
}
ll inverse(ll a,ll m){
return qpow(fact[a],m-2,m);
// if(a==0)
// return qpow(fact[0],m-2,m);
// return inv[a];
}
ll C(ll n,ll r,ll m){
if(r>n)
return 0;
return ((fact[n]*inverse(r,m))%m*inverse(n-r,m)%m);
}
ll Lucas(ll n,ll r,ll m){
if(r==0)
return 1;
return C(n%m,r%m,m)*Lucas(n/m,r/m,m)%m;
}
void init(ll n,ll p){
fact[0]=1;
for(int i=1;i<=n;i++)
fact[i]=(fact[i-1]*i)%p;
inv[1]=1;
for(int i=2;i<=N-5;i++){
inv[i]=(mod-mod/i)*inv[mod%i]%mod;
}
}
void slove(){
int n;
cin>>n;
init(n,mod);
ll ans=0;
if(n==1){
cout<<1<<endl;
return;
}
ll tot=1;
int j=n-1;
for(int i=1;i<=n/2;i++){
// ans+= Lucas(n-i,i-1,mod)*fact[i-1]%mod *fact[n-i]%mod;
// cout<<Lucas(n-i,i-1,mod)*fact[i-1]%mod *fact[n-i]%mod<<endl;
// ans%=mod;
for(;j>=n-2*i+2;j--){
tot*=j;
tot%=mod;
}
// cout<<tot<<endl;
ans+=tot*fact[n-i];
ans%=mod;
tot=tot*inv[n-i];
tot%=mod;
}
cout<<ans<<endl;
}
signed main(){
cin.tie(nullptr)->sync_with_stdio(0);
int _=1;
// cin>>_;
while(_--){
slove();
}
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 54ms
memory: 83308kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 59ms
memory: 82780kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 49ms
memory: 83752kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 46ms
memory: 81748kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 62ms
memory: 82364kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 51ms
memory: 81848kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 60ms
memory: 82196kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 59ms
memory: 83160kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 54ms
memory: 81752kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 64ms
memory: 83596kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 51ms
memory: 82624kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 63ms
memory: 81856kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 52ms
memory: 82920kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 60ms
memory: 94296kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: -100
Wrong Answer
time: 152ms
memory: 142344kb
input:
7579013
output:
693151411
result:
wrong answer 1st numbers differ - expected: '827172636', found: '693151411'