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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 |
---|---|---|---|---|---|---|---|---|---|
#766781 | #9553. The Hermit | DarwinA66 | WA | 340ms | 19484kb | C++20 | 1.4kb | 2024-11-20 18:35:50 | 2024-11-20 18:35:53 |
Judging History
answer
#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int N=100010;
ll mod=998244353;
ll fastpow(ll a,ll n)
{
ll base=a;
ll res=1ll;
while(n)
{
if(n&1ll)res=(res*base)%mod;
base=(base*base)%mod;
n>>=1;
}
return res;
}
ll mod_inverse(ll x)
{
ll res=fastpow(x,mod-2);
return res;
}
ll dp[N][20];
int main()
{
int n,m;
scanf("%d %d",&m,&n);
ll ans=0ll;
ll c=1ll*m;
for(int i=1;i<=m;i++)dp[i][1]=1ll;
for(int i=1;i<=m;i++)
{
for(int j=1;j<=17;j++)
{
for(int k=2;k*i<=m;k++)
{
dp[k*i][j+1]=(dp[i][j]+dp[k*i][j+1])%mod;
}
}
}
for(int i=2;i<=n;i++)
{
c=(c*(m+1ll-i*1ll))%mod;
c=(c*mod_inverse(i))%mod;
if(i==n)ans=(ans+((i*1ll*c)%mod))%mod;
}
for(int i=1;i<=m;i++)
{
int b=(m/i)-1;
int cc=1ll;
if(n<=19)ans=(((ans-dp[i][n])%mod)+mod)%mod;
for(int j=1;(j+1<=n)&&(j<=b);j++)
{
cc=(cc*(b*1ll+1ll-j*1ll))%mod;
cc=(cc*mod_inverse(j))%mod;
ll temp;
if((n-j<=19)&&n-j>=1)temp=dp[i][n-j];
else temp=0ll;
ans=((ans-(((temp*cc)%mod))%mod)+mod)%mod;
}
}
printf("%lld\n",ans);
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 3784kb
input:
4 3
output:
7
result:
ok 1 number(s): "7"
Test #2:
score: 0
Accepted
time: 0ms
memory: 3868kb
input:
11 4
output:
1187
result:
ok 1 number(s): "1187"
Test #3:
score: 0
Accepted
time: 340ms
memory: 19412kb
input:
100000 99999
output:
17356471
result:
ok 1 number(s): "17356471"
Test #4:
score: 0
Accepted
time: 23ms
memory: 7204kb
input:
11451 1919
output:
845616153
result:
ok 1 number(s): "845616153"
Test #5:
score: 0
Accepted
time: 280ms
memory: 19408kb
input:
99998 12345
output:
936396560
result:
ok 1 number(s): "936396560"
Test #6:
score: -100
Wrong Answer
time: 59ms
memory: 19484kb
input:
100000 1
output:
998144353
result:
wrong answer 1st numbers differ - expected: '0', found: '998144353'