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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#412884#6736. Alice and BobZhazTL 4ms5740kbC++171.6kb2024-05-16 21:03:252024-05-16 21:03:25

Judging History

你现在查看的是最新测评结果

  • [2024-05-16 21:03:25]
  • 评测
  • 测评结果:TL
  • 用时:4ms
  • 内存:5740kb
  • [2024-05-16 21:03:25]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ll long long
#define endl "\n"
#define PII pair<double,int>
const int maxn=1e7+5;
const int mod=998244353;
int dp[maxn],p[maxn];
ll pow(ll a, ll b, ll m)
{
    ll ans = 1;
    a %= m;
    while(b)
    {
        if(b & 1)ans = (ans % m) * (a % m) % m;
        b /= 2;
        a = (a % m) * (a % m) % m;
    }
    ans %= m;
    return ans;
}
ll inv(ll x, ll p)//x关于p的逆元,p为素数
{
    return pow(x, p - 2, p);
}
ll C(ll n, ll m, ll p)//组合数C(n, m) % p
{
    if(m > n)return 0;
    ll up = 1, down = 1;//分子分母;
    for(int i = n - m + 1; i <= n; i++)up = up * i % p;
    for(int i = 1; i <= m; i++)down = down * i % p;
    return up * inv(down, p) % p;
}
ll Lucas(ll n, ll m, ll p)
{
    if(m == 0)return 1;
    return C(n % p, m % p, p) * Lucas(n / p, m / p, p) % p;
}

signed main(){
    // ios::sync_with_stdio(false);
    // cin.tie(0),cout.tie(0);
    
    int n;cin>>n;
    p[1]=1;
    dp[1]=1;
    dp[2]=1;
    dp[3]=3;
    // dp[4]=10;
    for(int i=2;i<=n;i++){
        p[i]=p[i-1]*i;
        p[i]%=mod;
    }
    int ans=p[n-1];
    int s=1,x=n-2;
    for(int i=2;i<=n;i++){
        // int temp=Lucas(x,s,mod)*inv(Lucas(n-1,i-1,mod),mod);
        // temp*=p[n-1];
        // temp%=mod;
        int temp=Lucas(x,s,mod)*p[n-1]%mod;
        ans+=temp*inv(Lucas(n-1,i-1,mod),mod);
        ans%=mod;
        // printf("%d %d %d\n",s,x,p[n-1]);
        x--;s++;
        if(s>x)break;
        
    }
    if(n==1)ans=1;
    cout<<ans<<endl;


    
    
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 0ms
memory: 5672kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

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

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

score: 0
Accepted
time: 1ms
memory: 5668kb

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 1ms
memory: 5676kb

input:

100

output:

188898954

result:

ok 1 number(s): "188898954"

Test #5:

score: 0
Accepted
time: 1ms
memory: 5680kb

input:

4

output:

10

result:

ok 1 number(s): "10"

Test #6:

score: 0
Accepted
time: 1ms
memory: 5680kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

score: 0
Accepted
time: 0ms
memory: 5668kb

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

score: 0
Accepted
time: 1ms
memory: 5732kb

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 1ms
memory: 5592kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 0ms
memory: 5680kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 1ms
memory: 5672kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 2ms
memory: 5616kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 4ms
memory: 5740kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: -100
Time Limit Exceeded

input:

1361956

output:


result: