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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 |
---|---|---|---|---|---|---|---|---|---|
#776452 | #9553. The Hermit | windStrider | WA | 80ms | 8692kb | C++20 | 3.4kb | 2024-11-23 18:45:19 | 2024-11-23 18:45:19 |
Judging History
answer
#include<bits/stdc++.h>
using pii = std::pair<int, int>;
using i64 = long long;
static constexpr int mod = 998244353;
class combMath
{
public:
static constexpr int size = 2e5;
i64 fact[size + 1];
i64 finv[size + 1];
i64 inve[size + 1];
static constexpr int mod = 998244353;
void factor()
{
fact[0] = 1; fact[1] = 1;
inv();
finv[0] = 1;
finv[1] = inve[1];
for (int i = 2; i <= size; ++i) fact[i] = fact[i - 1] * i % mod, finv[i] = finv[i - 1] * inve[i] % mod;
}
void inv()
{
inve[1] = 1;
for (int i = 2; i <= size; ++i)
{
inve[i] = (mod - mod / i) * inve[mod % i] % mod;
}
}
public:
combMath() { factor(); }
i64 power(i64 x, i64 p)
{
i64 temp = p, ans = 1;
while (temp)
{
if (temp & 1) ans = ans * x % mod;
temp >>= 1;
x = x * x % mod;
}
return ans;
}
i64 getInv(i64 x)
{
return power(x, mod - 2);
}
i64 inv(i64 x)
{
return inve[x];
}
i64 facInv(i64 x)
{
return finv[x];
}
i64 getFac(i64 obj)
{
return fact[obj];
}
i64 perm(i64 n, i64 m, bool mode)
{
if (mode) return fact[n] * finv[n - m] % mod;
else return fact[n] / fact[n - m];
}
i64 comb(i64 n, i64 m, bool mode = 1)
{
if (mode) return fact[n] * finv[n - m] % mod * finv[m] % mod;
else return fact[n] / fact[n - m] / fact[m];
}
i64 stirling(i64 n, i64 m) // 'n' balls into 'm' boxes, boxes DO NOT differ while balls differ.
{
i64 ans = 0;
for (int i = 0; i < m; ++i)
ans = (ans + (i & 1 ? -1 : 1) * comb(m, i, 1) * power(m - i, n) % mod) % mod;
ans = ans * finv[m] % mod;
return (ans + mod) % mod;
}
i64 catalan(int n, int mode) // n different nums pop in a stack in an certain order, how many ramifications there will be.
{
std::vector<i64> dp(n + 1, 1);
if (mode) for (int i = 1; i <= n; ++i) dp[i] = dp[i - 1] * (4LL * i % mod - 2) % mod * inv(i + 1) % mod;
else for (int i = 1; i <= n; ++i) dp[i] = dp[i - 1] * (4 * i - 2) / (i + 1);
return dp[n];
}
} cm;
const int N = 1e5 + 1;
using namespace std;
int cnt[N];
void solve()
{
for (int i = 2; i <= 1e5; ++i)
{
int tmp = i;
for (int j = 2; j <= i / j; ++j)
{
while (tmp % j == 0) tmp /= j, ++cnt[i];
}
if (tmp > 1) ++cnt[i];
}
// for (int i = 2; i < 100; ++i)
// {
// std::cout << cnt[i] << "\n";
// }
int m,n;
std::cin >> m >> n;
long long suml = cm.comb(m,n) * n % mod;
for(int i = 1;i <= m;i++){
//cout << cnt[i] << endl;
//std::cout << suml << endl;
if(i == 1){
suml = (suml + mod - cm.comb(m-1,n-1) % mod) % mod;
}
else{
//cnt[i]++;
long long mm = m / i - 1;
for(int j = 0;j <= cnt[i];j++){
if(j + mm + 1 >= n && j + 1 <= n)
suml = (suml + mod -(cm.comb(cnt[i],j) * cm.comb(mm,n-j-1))%mod)%mod;
}
}
}
std::cout << suml;
}
int main()
{
// int t;
// std::cin >> t;
// while (t--)
// {
// solve();
// }
solve();
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 80ms
memory: 8564kb
input:
4 3
output:
7
result:
ok 1 number(s): "7"
Test #2:
score: 0
Accepted
time: 76ms
memory: 8684kb
input:
11 4
output:
1187
result:
ok 1 number(s): "1187"
Test #3:
score: 0
Accepted
time: 78ms
memory: 8616kb
input:
100000 99999
output:
17356471
result:
ok 1 number(s): "17356471"
Test #4:
score: 0
Accepted
time: 80ms
memory: 8692kb
input:
11451 1919
output:
845616153
result:
ok 1 number(s): "845616153"
Test #5:
score: -100
Wrong Answer
time: 77ms
memory: 8616kb
input:
99998 12345
output:
937364469
result:
wrong answer 1st numbers differ - expected: '936396560', found: '937364469'