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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#361961#6736. Alice and BobSusie_Rain#AC ✓120ms159928kbC++201.1kb2024-03-23 13:44:102024-03-23 13:44:12

Judging History

你现在查看的是最新测评结果

  • [2024-03-23 13:44:12]
  • 评测
  • 测评结果:AC
  • 用时:120ms
  • 内存:159928kb
  • [2024-03-23 13:44:10]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD = 998244353;
const int N = 1e7 + 1;
ll qpow(ll a,ll k){
    ll res = 1;
    while (k){
        if(k&1) res = res * a % MOD;
        a = a * a % MOD;
        k >>= 1;
    }
    return res;
}
ll fac[N] , infac[N];
void init(int N){
    fac[1] = 1 ;
    for(int i=2;i<N;i++){
        fac[i] = ( 1ll*fac[i-1] * i + MOD ) % MOD ;
    }
    fac[0] = 1 , infac[0] = 1 ;
    infac[N-1] = qpow(fac[N-1],MOD-2);
    for(int i=N-2;i>=1;i--){
        infac[i] = 1ll*(i+1)*infac[i+1]%MOD ;
    }
}
int C(int a,int b){
    if(b==0) return 1;
    if(a < b) return 0;
    return 1ll*fac[a]*infac[b]%MOD*infac[a-b]%MOD;
}
void solve(){
    int n;
    cin >> n;
    init(n+1);
    ll ans = 0;
    for(int i=1;i<=n;i++){
        if(2*i > n + 1) break;
        ans += C(n-i,i-1) * fac[n-i] % MOD * fac[i-1] % MOD;
        ans %= MOD;
    }
    cout << ans << '\n';
}
signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int tt = 1;
//    cout << 997920 * 4 << '\n';
//    cin >> tt;
    while (tt--) solve();
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 5596kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 0ms
memory: 5596kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 1ms
memory: 5664kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 1ms
memory: 5696kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 1ms
memory: 5704kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 1ms
memory: 5612kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 1ms
memory: 5692kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 1ms
memory: 5660kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 0ms
memory: 5752kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 1ms
memory: 5612kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 1ms
memory: 5656kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 1ms
memory: 5752kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 0ms
memory: 5760kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: 0
Accepted
time: 20ms
memory: 27360kb

input:

1361956

output:

617368199

result:

ok 1 number(s): "617368199"

Test #15:

score: 0
Accepted
time: 90ms
memory: 125288kb

input:

7579013

output:

827172636

result:

ok 1 number(s): "827172636"

Test #16:

score: 0
Accepted
time: 98ms
memory: 133652kb

input:

8145517

output:

710624331

result:

ok 1 number(s): "710624331"

Test #17:

score: 0
Accepted
time: 78ms
memory: 101032kb

input:

6140463

output:

707600568

result:

ok 1 number(s): "707600568"

Test #18:

score: 0
Accepted
time: 33ms
memory: 60300kb

input:

3515281

output:

698302413

result:

ok 1 number(s): "698302413"

Test #19:

score: 0
Accepted
time: 86ms
memory: 114488kb

input:

6969586

output:

69470392

result:

ok 1 number(s): "69470392"

Test #20:

score: 0
Accepted
time: 16ms
memory: 52460kb

input:

2888636

output:

433579983

result:

ok 1 number(s): "433579983"

Test #21:

score: 0
Accepted
time: 114ms
memory: 159896kb

input:

9999998

output:

758172780

result:

ok 1 number(s): "758172780"

Test #22:

score: 0
Accepted
time: 119ms
memory: 159928kb

input:

9999999

output:

605195495

result:

ok 1 number(s): "605195495"

Test #23:

score: 0
Accepted
time: 120ms
memory: 159852kb

input:

10000000

output:

866813682

result:

ok 1 number(s): "866813682"