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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#693928#6736. Alice and BobR73757565#RE 1ms7812kbC++231.1kb2024-10-31 16:58:482024-10-31 16:58:50

Judging History

你现在查看的是最新测评结果

  • [2024-10-31 16:58:50]
  • 评测
  • 测评结果:RE
  • 用时:1ms
  • 内存:7812kb
  • [2024-10-31 16:58:48]
  • 提交

answer

#include<bits/stdc++.h>
using namespace std;

typedef pair<int, int> PII;
typedef long long LL;

const int N = 2e5 + 10, mod = 998244353;
int q_pow(int a, int b){
    int res = 1ll % mod;
    while(b){
        if(b & 1)res = res * a % mod;
        a = a * a % mod, b>>= 1;
    }
    return res;
}
LL fac[N];
LL jv[N], inv[N];
void C_init(int n) {
    inv[1] = 1;
    for (int i = 2; i <= n; i++) {
        inv[i] = (mod - mod / i) * inv[mod % i] % mod;
    }
    jv[0] = fac[0] = 1;
    for (int i = 1; i <= n; i++) {
        fac[i] = fac[i - 1] * i % mod;
        jv[i] = jv[i - 1] * inv[i] % mod;
    }
}
LL C(int n, int m) {
    if (n < m || m < 0) return 0;
    return fac[n] * jv[n - m] % mod * jv[m] % mod;
}
LL A(int n,int m){
    return C(n,m)*fac[m]%mod;
}
LL lucas(int n, int m) {
    if (m == 0) return 1;
    return C(n % mod, m % mod) * lucas(n / mod, m / mod) % mod;
}

signed main(){
    LL n;
    cin >> n;
    C_init(n+10);
    LL ans = 0;
    LL x=n-1,y=0;
    while(x>=y){
        ans=(ans+A(x,y)*A(x,x)%mod)%mod;
        x--,y++;
    }
    cout<<ans<<endl;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 1ms
memory: 7724kb

input:

1

output:

1

result:

ok 1 number(s): "1"

Test #2:

score: 0
Accepted
time: 1ms
memory: 5748kb

input:

2

output:

1

result:

ok 1 number(s): "1"

Test #3:

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

input:

10

output:

997920

result:

ok 1 number(s): "997920"

Test #4:

score: 0
Accepted
time: 0ms
memory: 7808kb

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: 0ms
memory: 5672kb

input:

8

output:

12336

result:

ok 1 number(s): "12336"

Test #7:

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

input:

16

output:

373118483

result:

ok 1 number(s): "373118483"

Test #8:

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

input:

32

output:

314585464

result:

ok 1 number(s): "314585464"

Test #9:

score: 0
Accepted
time: 0ms
memory: 5764kb

input:

64

output:

627827331

result:

ok 1 number(s): "627827331"

Test #10:

score: 0
Accepted
time: 1ms
memory: 7736kb

input:

128

output:

828497685

result:

ok 1 number(s): "828497685"

Test #11:

score: 0
Accepted
time: 1ms
memory: 5756kb

input:

256

output:

65697890

result:

ok 1 number(s): "65697890"

Test #12:

score: 0
Accepted
time: 1ms
memory: 7812kb

input:

512

output:

854187619

result:

ok 1 number(s): "854187619"

Test #13:

score: 0
Accepted
time: 1ms
memory: 5780kb

input:

1024

output:

513823539

result:

ok 1 number(s): "513823539"

Test #14:

score: -100
Runtime Error

input:

1361956

output:


result: