QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#407290 | #6736. Alice and Bob | tjf4# | AC ✓ | 118ms | 159916kb | C++20 | 1.1kb | 2024-05-08 14:24:09 | 2024-05-08 14:24:18 |
Judging History
answer
#include<bits/stdc++.h>
#define IOS ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
using namespace std;
typedef double db;
typedef long long ll;
typedef pair<ll,ll> pii;
typedef vector<pii> vii;
typedef vector<ll> vi;
typedef vector<string> vs;
typedef vector<char> vc;
const int inf=0x3f;
const int N=1e7+10;
const int mod=998244353;
ll q[N],inv[N];
ll pow_mod(ll a,ll b) {
ll res=1;
while(b) {
if(b&1) res=(res*a)%mod;
b>>=1;
a=(a*a)%mod;
}
return res;
}
void init() {
q[0]=1;
for(int i=1;i<N;i++) q[i]=q[i-1]*i%mod;
inv[N-1]=pow_mod(q[N-1],mod-2);
for(int i=N-1;i>=1;i--) inv[i-1]=inv[i]*i%mod;
}
ll C(ll n,ll m) {
if(n<m||n<0||m<0) return 0;
if(n==m||m==0) return 1;
return q[n]*inv[m]%mod*inv[n-m]%mod;
}
ll n;
int main() {
init();
cin>>n;
ll res=0;
for(int i=1;i<=n;i++) {//以i为第一个
ll x=i-1;//后面有几个位置
ll y=n-i;//比i大的选x个填入
if(y<x) break;
ll su=C(y,x)*q[x]%mod*q[n-i]%mod;
res+=su;
if(res>=mod) res-=mod;
}
cout<<res%mod;
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 81ms
memory: 159748kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 84ms
memory: 159892kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 92ms
memory: 159824kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 86ms
memory: 159804kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 72ms
memory: 159916kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 89ms
memory: 159808kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 72ms
memory: 159912kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 82ms
memory: 159820kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 80ms
memory: 159820kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 81ms
memory: 159880kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 80ms
memory: 159892kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 89ms
memory: 159736kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 70ms
memory: 159824kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 92ms
memory: 159792kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 107ms
memory: 159864kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 100ms
memory: 159740kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 103ms
memory: 159828kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 92ms
memory: 159744kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 118ms
memory: 159844kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 90ms
memory: 159744kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 117ms
memory: 159740kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 114ms
memory: 159820kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 106ms
memory: 159808kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"