QOJ.ac
QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#795209 | #9553. The Hermit | Gordios_knot | WA | 458ms | 38672kb | C++14 | 1.4kb | 2024-11-30 18:39:04 | 2024-11-30 18:39:04 |
Judging History
answer
#include<bits/stdc++.h>
using namespace std;
namespace D {
typedef long long ll;
const int p = 998244353;
const int N = 1e5 + 5;
ll qp(ll a, ll b) {
ll z = 1;
while(b) {
if(b & 1) z = 1ll * z * a % p;
a %= p;
a = a * a;
a %= p;
b >>= 1;
}
return z;
}
ll fac[N], ifac[N];
ll C(int a, int b) {
if (a < b || b < 0) return 0;
return (((fac[a] * ifac[b]) % p) * ifac[a - b]) % p;
}
unordered_map<int, unordered_map<int, ll> > nums;
ll ans = 0;
void work() {
ll n, m;
cin >> m >> n;
fac[0] = 1;
for (int i = 1; i < N; i++) fac[i] = (fac[i - 1] * i) % p;
ifac[N - 1] = qp(fac[N - 1], p - 2);
for (int i = N - 1; i; i--) ifac[i - 1] = (ifac[i] * i) % p;
for (int i = 1; i <= m; i++) {
nums[i][1] = 1;
}
for (int i = 1; i <= m; i++) {
for (int j = 2 * i; j <= m; j += i) {
for (auto it = nums[i].begin(); it != nums[i].end() && it->first < n; it++) {
nums[j][it->first + 1] = (nums[j][it->first + 1] + it->second) % p;
}
}
}
ans = (C(m, n) * n) % p;
for (int i = 1; i <= m; i++) {
for (auto it = nums[i].begin(); it != nums[i].end(); it++) {
ans = (((ans - it->second * C(m / i - 1, n - it->first)) % p) + p) % p;
}
}
cout << ans << '\n';
}
}
int main (void) {
ios::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
D::work();
return 0;
}
Details
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Test #1:
score: 100
Accepted
time: 2ms
memory: 5188kb
input:
4 3
output:
7
result:
ok 1 number(s): "7"
Test #2:
score: 0
Accepted
time: 0ms
memory: 5188kb
input:
11 4
output:
1187
result:
ok 1 number(s): "1187"
Test #3:
score: 0
Accepted
time: 458ms
memory: 38672kb
input:
100000 99999
output:
17356471
result:
ok 1 number(s): "17356471"
Test #4:
score: 0
Accepted
time: 14ms
memory: 8780kb
input:
11451 1919
output:
845616153
result:
ok 1 number(s): "845616153"
Test #5:
score: 0
Accepted
time: 417ms
memory: 38536kb
input:
99998 12345
output:
936396560
result:
ok 1 number(s): "936396560"
Test #6:
score: 0
Accepted
time: 23ms
memory: 27984kb
input:
100000 1
output:
0
result:
ok 1 number(s): "0"
Test #7:
score: -100
Wrong Answer
time: 425ms
memory: 38496kb
input:
100000 15
output:
190072311
result:
wrong answer 1st numbers differ - expected: '190067060', found: '190072311'