QOJ.ac
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 |
---|---|---|---|---|---|---|---|---|---|
#790953 | #6736. Alice and Bob | HJR# | AC ✓ | 204ms | 238072kb | C++17 | 1.3kb | 2024-11-28 16:10:59 | 2024-11-28 16:11:00 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
#define endl "\n"
#define debug(x) cout<<#x<<": "<<x<<endl
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
using ll=long long;
using ull=unsigned long long;
const int mo=998244353;
const int N=1e7+10;
#define int long long
int ksm(int a,int b,int p){
int res=1;
while(b){
if(b&2)
res=res*a%p;
a=a*a%p;
b>>=1;
}
return res;
}
int fac[N],infac[N],inv[N];
void init(int n){
fac[0]=1;
for(int i=1;i<=n;i++){
fac[i]=fac[i-1]*i%mo;
}
inv[0]=0;
inv[1]=1;
for(int i=2;i<=n;i++){
inv[i]=mo-(mo/i*inv[mo%i]%mo)%mo;
}
infac[0]=1;
for(int i=1;i<=n;i++){
infac[i]=infac[i-1]*inv[i]%mo;
}
}
int C(int a,int b){
if(a<b)
return 0;
return fac[a]*infac[b]%mo*infac[a-b]%mo;
}
void solve(){
int n;
cin>>n;
init(n);
int ans=0;
for(int i=1;i<=n;i++){
// debug(C(i,i));
ans+=C(n-i,i-1)*fac[i-1]%mo*fac[n-i]%mo;
ans%=mo;
}
cout<<ans<<endl;
}
signed main(){
ios::sync_with_stdio(0);
cout.tie(0);
cin.tie(0);
int t=1;
while(t--){
solve();
}
}
/*
贡献法
正难则反
数小状压
关系连边
拆位
广义单调性
最长转最短
*/
详细
Test #1:
score: 100
Accepted
time: 1ms
memory: 7812kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 7660kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 1ms
memory: 7712kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 1ms
memory: 7676kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 1ms
memory: 7720kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 1ms
memory: 7684kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 1ms
memory: 7712kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 7656kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 0ms
memory: 7680kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 0ms
memory: 7716kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 0ms
memory: 7680kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 1ms
memory: 7816kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 0ms
memory: 7724kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 23ms
memory: 39984kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 150ms
memory: 186212kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 173ms
memory: 199848kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 120ms
memory: 155840kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 61ms
memory: 89816kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 141ms
memory: 169432kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 54ms
memory: 77260kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 178ms
memory: 238072kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 200ms
memory: 237996kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 204ms
memory: 238068kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"