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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 |
---|---|---|---|---|---|---|---|---|---|
#778610 | #9553. The Hermit | aYi_7# | WA | 252ms | 5404kb | C++23 | 1.6kb | 2024-11-24 15:26:40 | 2024-11-24 15:26:40 |
Judging History
answer
#include <bits/stdc++.h>
#define int long long
using namespace std;
const int mod = 998244353;
const int N = 1e5 + 7;
int fac[N], inv[N];
int qmi(int a, int b) {
a %= mod;
int res = 1;
while (b) {
if (b & 1) res = res * a % mod;
a = a * a % mod;
b >>= 1;
}
return res;
}
void init() {
fac[0] = inv[0] = fac[1] = inv[1] = 1;
for (int i = 2; i < N; i++) fac[i] = i * fac[i - 1] % mod;
inv[N - 1] = qmi(fac[N - 1], mod - 2ll);
for (int i = N - 2; i > 1; i--) inv[i] = (int)(i + 1) * inv[i + 1] % mod;
}
//int A(int a,int b){return fac[a]*inv[a-b]%mod;}
int C(int a, int b) {
if(b==0||b==a)return 1;
if(b>a)return 0;
return fac[a] * inv[a - b] % mod * inv[b] % mod;
}
void solve() {
int m,n;
cin>>m>>n;
int ans=n*C(m,n)%mod;
for(int i=1;i<=m;i++){
int b=m/i-1ll;
map<int,int>hh;
int id=i,c=0;
for(int j=2;j*j<=i;j++)
while(id%j==0){
id/=j;
hh[j]++;
c++;
}
if(id>1){
hh[id]++;
c++;
}
int s=1;
for(auto &[k,j]:hh)s=s*inv[j]%mod;
for(int j=1;j<=min(500ll,n);j++){
int sub=C(c,j-1)*fac[c]%mod;
sub=sub*s%mod;
sub= sub * C(b,n-j) %mod;
ans=(ans+mod-sub)%mod;
}
}
cout<<ans<<"\n";
}
signed main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
init();
int t = 1;
// std::cin >> t;
for (int i = 0; i < t; ++i) {
solve();
}
return 0;
}
詳細信息
Test #1:
score: 100
Accepted
time: 0ms
memory: 5168kb
input:
4 3
output:
7
result:
ok 1 number(s): "7"
Test #2:
score: 0
Accepted
time: 2ms
memory: 5164kb
input:
11 4
output:
1187
result:
ok 1 number(s): "1187"
Test #3:
score: 0
Accepted
time: 249ms
memory: 5208kb
input:
100000 99999
output:
17356471
result:
ok 1 number(s): "17356471"
Test #4:
score: 0
Accepted
time: 22ms
memory: 5404kb
input:
11451 1919
output:
845616153
result:
ok 1 number(s): "845616153"
Test #5:
score: -100
Wrong Answer
time: 252ms
memory: 5116kb
input:
99998 12345
output:
42538319
result:
wrong answer 1st numbers differ - expected: '936396560', found: '42538319'