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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 |
|---|---|---|---|---|---|---|---|---|---|
| #533840 | #6736. Alice and Bob | hzjoiineg | AC ✓ | 104ms | 159928kb | C++20 | 659b | 2024-08-26 15:29:25 | 2024-08-26 15:29:25 |
Judging History
answer
#include<bits/stdc++.h>
#define rep(i, j, k) for(int i=j;i<=k;i++)
#define rep1(i, j, k) for(int i=k;i>=j;i--)
#define ll long long
using namespace std;
const int N=1e7+5, mod=998244353;
int n;
ll s[N], inv[N], ans;
ll ksm(ll a, int b){
ll res=1;
while(b){
if(b&1) res=res*a%mod;
a=a*a%mod, b>>=1;
}
return res;
}
void add(ll &a, ll b){
a=a+b-(a+b>=mod)*mod;
}
int main(){
cin>>n;
s[0]=inv[0]=1;
rep(i, 1, n) s[i]=s[i-1]*i%mod;
inv[n]=ksm(s[n], mod-2);
rep1(i, 1, n-1) inv[i]=inv[i+1]*(i+1)%mod;
int m=(n+1)>>1;
rep(i, 1, m) add(ans, s[n-i]*s[n-i]%mod*inv[n-i-i+1]%mod);
cout<<ans<<endl;
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 1ms
memory: 5676kb
input:
1
output:
1
result:
ok 1 number(s): "1"
Test #2:
score: 0
Accepted
time: 1ms
memory: 5672kb
input:
2
output:
1
result:
ok 1 number(s): "1"
Test #3:
score: 0
Accepted
time: 0ms
memory: 5584kb
input:
10
output:
997920
result:
ok 1 number(s): "997920"
Test #4:
score: 0
Accepted
time: 1ms
memory: 5580kb
input:
100
output:
188898954
result:
ok 1 number(s): "188898954"
Test #5:
score: 0
Accepted
time: 0ms
memory: 5604kb
input:
4
output:
10
result:
ok 1 number(s): "10"
Test #6:
score: 0
Accepted
time: 0ms
memory: 5656kb
input:
8
output:
12336
result:
ok 1 number(s): "12336"
Test #7:
score: 0
Accepted
time: 1ms
memory: 5732kb
input:
16
output:
373118483
result:
ok 1 number(s): "373118483"
Test #8:
score: 0
Accepted
time: 1ms
memory: 5588kb
input:
32
output:
314585464
result:
ok 1 number(s): "314585464"
Test #9:
score: 0
Accepted
time: 1ms
memory: 5732kb
input:
64
output:
627827331
result:
ok 1 number(s): "627827331"
Test #10:
score: 0
Accepted
time: 1ms
memory: 5652kb
input:
128
output:
828497685
result:
ok 1 number(s): "828497685"
Test #11:
score: 0
Accepted
time: 1ms
memory: 5728kb
input:
256
output:
65697890
result:
ok 1 number(s): "65697890"
Test #12:
score: 0
Accepted
time: 1ms
memory: 5588kb
input:
512
output:
854187619
result:
ok 1 number(s): "854187619"
Test #13:
score: 0
Accepted
time: 0ms
memory: 5548kb
input:
1024
output:
513823539
result:
ok 1 number(s): "513823539"
Test #14:
score: 0
Accepted
time: 7ms
memory: 27308kb
input:
1361956
output:
617368199
result:
ok 1 number(s): "617368199"
Test #15:
score: 0
Accepted
time: 63ms
memory: 122624kb
input:
7579013
output:
827172636
result:
ok 1 number(s): "827172636"
Test #16:
score: 0
Accepted
time: 81ms
memory: 133940kb
input:
8145517
output:
710624331
result:
ok 1 number(s): "710624331"
Test #17:
score: 0
Accepted
time: 57ms
memory: 102856kb
input:
6140463
output:
707600568
result:
ok 1 number(s): "707600568"
Test #18:
score: 0
Accepted
time: 34ms
memory: 61944kb
input:
3515281
output:
698302413
result:
ok 1 number(s): "698302413"
Test #19:
score: 0
Accepted
time: 71ms
memory: 115396kb
input:
6969586
output:
69470392
result:
ok 1 number(s): "69470392"
Test #20:
score: 0
Accepted
time: 33ms
memory: 51492kb
input:
2888636
output:
433579983
result:
ok 1 number(s): "433579983"
Test #21:
score: 0
Accepted
time: 104ms
memory: 159848kb
input:
9999998
output:
758172780
result:
ok 1 number(s): "758172780"
Test #22:
score: 0
Accepted
time: 96ms
memory: 159928kb
input:
9999999
output:
605195495
result:
ok 1 number(s): "605195495"
Test #23:
score: 0
Accepted
time: 92ms
memory: 159776kb
input:
10000000
output:
866813682
result:
ok 1 number(s): "866813682"