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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 |
---|---|---|---|---|---|---|---|---|---|
#768881 | #9553. The Hermit | AiriS# | RE | 13ms | 10368kb | C++14 | 991b | 2024-11-21 15:02:14 | 2024-11-21 15:02:21 |
Judging History
answer
#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<map>
using namespace std;
#define int long long
int n,m;
const int N=110000,P=998244353;
int quickpow(int a,int b){
int ans=1,base=a;
while(b){
if(b&1)(ans*=base)%=P;
(base*=base)%=P;
b>>=1;
}
return ans;
}
int jc[N],inv[N];
void pre(int n){
jc[0]=1;
for(int i=1;i<=n;i++)jc[i]=jc[i-1]*i%P;
for(int i=0;i<=n;i++)inv[i]=quickpow(jc[i],P-2);
}
int C(int a,int b){
if(a<b)return 0;
return jc[a]*inv[b]%P*inv[a-b]%P;
}
map<int,int> F[N];
int f(int n,int m){
if(n>=m)return 0;
if(F[n][m])return F[n][m];
int ans=C(m-1,n)*n%P;
for(int l=2,r;l<=m;l=r+1){
r=m/(m/l);
(ans+=(r-l+1)*f(n-1,m/l)%P-(r-l+1)*C(m/l-1,n-1)%P*n%P)%=P;
}
//cerr<<n<<' '<<m<<' '<<ans<<'\n';
return F[n][m]=(ans+P)%P;
}
signed main(){
int n,m;cin>>m>>n;pre(m);
cout<<(f(n,m)+f(n-1,m))%P;
}
詳細信息
Test #1:
score: 100
Accepted
time: 0ms
memory: 8760kb
input:
4 3
output:
7
result:
ok 1 number(s): "7"
Test #2:
score: 0
Accepted
time: 2ms
memory: 9944kb
input:
11 4
output:
1187
result:
ok 1 number(s): "1187"
Test #3:
score: 0
Accepted
time: 13ms
memory: 10348kb
input:
100000 99999
output:
17356471
result:
ok 1 number(s): "17356471"
Test #4:
score: 0
Accepted
time: 2ms
memory: 9824kb
input:
11451 1919
output:
845616153
result:
ok 1 number(s): "845616153"
Test #5:
score: 0
Accepted
time: 10ms
memory: 10368kb
input:
99998 12345
output:
936396560
result:
ok 1 number(s): "936396560"
Test #6:
score: -100
Runtime Error
input:
100000 1