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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 |
|---|---|---|---|---|---|---|---|---|---|
| #415111 | #6678. Gem Island 2 | Flamire | TL | 266ms | 239968kb | C++17 | 1.8kb | 2024-05-20 11:05:03 | 2024-05-20 11:05:04 |
Judging History
answer
#include <bits/stdc++.h>
#define N 30000011
using namespace std;
int n,d,r,fac[N],ifac[N],R[N];const int p=998244353;
inline int qpow(int bs,int ex){int ans=1;while(ex){if(ex&1)ans=1ll*ans*bs%p;ex>>=1;bs=1ll*bs*bs%p;}return ans;}
inline int binom(int n,int m){if(n<m||m<0)return 0;return 1ll*fac[n]*ifac[m]%p*ifac[n-m]%p;}
int Sn(int n,int m)
{//printf("Sn(%d,%d)\n",n,m);
if(m<0)return 0;
if(!n)return 1;
// int ans=0;
// for(int i=0;i<=m;++i)ans=(ans+binom(n,i)*(i&1?-1:1))%p;
// printf("ans:%d ret:%d\n",ans,m&1?-binom(n-1,m):binom(n-1,m));
return m&1?-binom(n-1,m):binom(n-1,m);
}
int main()
{
scanf("%d%d%d",&n,&d,&r);
if(!d){printf("%d\n",r);return 0;}
fac[0]=1;for(int i=1;i<N;++i)fac[i]=1ll*fac[i-1]*i%p;
ifac[N-1]=qpow(fac[N-1],p-2);for(int i=N-2;~i;--i)ifac[i]=1ll*ifac[i+1]*(i+1)%p;
int ans=0;
for(int j=1;j<=d;++j)
{
R[j]=(1ll*j*-Sn(j-1,r-1)+1ll*r*-Sn(j,r))%p*binom(n,j)%p;
}
for(int x=2;x<=d+1;++x)
{
// printf("====================x:%d\n",x);
// for(int j=1;n+d-(x-1)*j-1>=n-1;++j)
// {
// ans=(ans+(j&1?-1ll:1ll)*binom(n,j)*binom(n+d-(x-1)*j-1,n-1)%p*(Sn[j]-1))%p;
// }
// for(int k=1;k<=r;++k)
// {
// for(int i=k;i<=n;++i)
// {
// for(int j=i;n+d-(x-1)*j-1>=n-1&&j<=n;++j)
// {
// ans=(ans+(j-i&1?-1ll:1ll)*binom(j,i)*binom(n,j)%p*binom(n+d-(x-1)*j-1,n-1))%p;
// }
// printf("x:%d k:%d i:%d ans:%d\n",x,k,i,ans);
// }
// printf("x:%d k:%d ans:%d\n",x,k,ans);
// }
for(int j=1;n+d-(x-1)*j-1>=n-1;++j)
{
int coe=(j&1?-1:1)*binom(n+d-(x-1)*j-1,n-1);
ans=(ans+1ll*coe*R[j])%p;
}
// printf("ans:%d\n",ans);
}
// printf("ans:%d\n",ans);
int denom=binom(n+d-1,n-1);
// printf("denom:%d\n",denom);
printf("%d\n",(1ll*ans*qpow(denom,p-2)%p+r+p)%p);
fclose(stdin);fclose(stdout);return 0;
}
详细
Test #1:
score: 100
Accepted
time: 258ms
memory: 239324kb
input:
2 3 1
output:
499122180
result:
ok 1 number(s): "499122180"
Test #2:
score: 0
Accepted
time: 253ms
memory: 238676kb
input:
3 3 2
output:
698771052
result:
ok 1 number(s): "698771052"
Test #3:
score: 0
Accepted
time: 255ms
memory: 238996kb
input:
5 10 3
output:
176512750
result:
ok 1 number(s): "176512750"
Test #4:
score: 0
Accepted
time: 254ms
memory: 239968kb
input:
5 4 3
output:
71303175
result:
ok 1 number(s): "71303175"
Test #5:
score: 0
Accepted
time: 254ms
memory: 238336kb
input:
37 47 12
output:
962577218
result:
ok 1 number(s): "962577218"
Test #6:
score: 0
Accepted
time: 257ms
memory: 238604kb
input:
29 50 26
output:
175627840
result:
ok 1 number(s): "175627840"
Test #7:
score: 0
Accepted
time: 258ms
memory: 238464kb
input:
298 498 221
output:
765832019
result:
ok 1 number(s): "765832019"
Test #8:
score: 0
Accepted
time: 258ms
memory: 239296kb
input:
497 456 243
output:
414028615
result:
ok 1 number(s): "414028615"
Test #9:
score: 0
Accepted
time: 266ms
memory: 239832kb
input:
114514 1926 817
output:
691374994
result:
ok 1 number(s): "691374994"
Test #10:
score: 0
Accepted
time: 261ms
memory: 239768kb
input:
1919810 1554 1999
output:
3553
result:
ok 1 number(s): "3553"
Test #11:
score: 0
Accepted
time: 249ms
memory: 238568kb
input:
1926817 1514 1001
output:
685086550
result:
ok 1 number(s): "685086550"
Test #12:
score: 0
Accepted
time: 242ms
memory: 238564kb
input:
1432132 1425 1425
output:
2850
result:
ok 1 number(s): "2850"
Test #13:
score: -100
Time Limit Exceeded
input:
14999999 15000000 14999999