#include <iostream>
#include <iomanip>
#include <algorithm>
#include <numeric>
#include <cmath>
#include <cassert>
#include <ctime>
#include <chrono>
#include <cstdio>
#include <random>
#include <vector>
#include <string>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <deque>
#include <queue>
#include <bitset>
#include <list>
#include <fstream>
#include <functional>
#include <complex>
using namespace std;
mt19937_64 rnd(chrono::steady_clock::now().time_since_epoch().count());
short skip_cin = 0;
const long long INF = 1e9, MOD = 1e9 + 7, MOD2 = 998244353, LOG = 19;
const long double EPS = 1e-9, PI = acos(-1);
void solve()
{
long long n, k;
vector<pair<double, double>> v;
cin >> n >> k;
v.resize(n);
for (long long i = 0; i < n; i++)
{
cin >> v[i].first >> v[i].second;
if (v[i].second == -1)
{
v[i].second = INF;
}
}
sort(v.begin(), v.end(),
[](pair<double, double>& x, pair<double, double>& y)
{
if (x.second == y.second)
{
return x.first < y.first;
}
return x.second < y.second;
}
);
vector<vector<double>> dp(k + 1, vector<double>(k + 1, INF));
dp[0][0] = 0;
for (long long i = 0; i < n; i++)
{
vector<vector<double>> upd(k + 1, vector<double>(k + 1, INF));
for (long long fr = 0; fr < k + 1; fr++)
{
for (long long hv = 0; hv < k + 1; hv++)
{
if (hv > 0)
{
if (dp[fr][hv - 1] != INF)
{
upd[fr][hv] = dp[fr][hv - 1] + v[i].first / (double)(fr + 1);
}
if (fr > 0 && v[i].second != INF && dp[fr - 1][hv - 1] != INF)
{
upd[fr][hv] = min(upd[fr][hv], dp[fr - 1][hv - 1] + v[i].second / (double)fr);
}
}
upd[fr][hv] = min(upd[fr][hv], dp[fr][hv]);
}
}
swap(dp, upd);
}
double ans = INF;
for (long long i = 0; i < k + 1; i++)
{
ans = min(ans, dp[i][k]);
}
cout << fixed << setprecision(20) << ans << "\n";
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
srand(time(NULL));
int tst = 1;
//cin >> tst;
while (tst--)
{
solve();
}
return 0;
}
/*
<3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3
⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⠤⠖⠚⢉⣩⣭⡭⠛⠓⠲⠦⣄⡀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⢀⡴⠋⠁⠀⠀⠊⠀⠀⠀⠀⠀⠀⠀⠀⠀⠉⠳⢦⡀⠀⠀⠀⠀
⠀⠀⠀⠀⢀⡴⠃⢀⡴⢳⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠙⣆⠀⠀⠀
⠀⠀⠀⠀⡾⠁⣠⠋⠀⠈⢧⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⢧⠀⠀
⠀⠀⠀⣸⠁⢰⠃⠀⠀⠀⠈⢣⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⣇⠀
⠀⠀⠀⡇⠀⡾⡀⠀⠀⠀⠀⣀⣹⣆⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⠀
⠀⠀⢸⠃⢀⣇⡈⠀⠀⠀⠀⠀⠀⢀⡑⢄⡀⢀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⡇
⠀⠀⢸⠀⢻⡟⡻⢶⡆⠀⠀⠀⠀⡼⠟⡳⢿⣦⡑⢄⠀⠀⠀⠀⠀⠀⠀⠀⢸⡇
⠀⠀⣸⠀⢸⠃⡇⢀⠇⠀⠀⠀⠀⠀⡼⠀⠀⠈⣿⡗⠂⠀⠀⠀⠀⠀⠀⠀⢸⠁
⠀⠀⡏⠀⣼⠀⢳⠊⠀⠀⠀⠀⠀⠀⠱⣀⣀⠔⣸⠁⠀⠀⠀⠀⠀⠀⠀⢠⡟⠀
⠀⠀⡇⢀⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠠⠀⡇⠀⠀⠀⠀⠀⠀⠀⠀⢸⠃⠀
⠀⢸⠃⠘⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⠁⠀⠀⢀⠀⠀⠀⠀⠀⣾⠀⠀
⠀⣸⠀⠀⠹⡄⠀⠀⠈⠁⠀⠀⠀⠀⠀⠀⠀⡞⠀⠀⠀⠸⠀⠀⠀⠀⠀⡇⠀⠀
⠀⡏⠀⠀⠀⠙⣆⠀⠀⠀⠀⠀⠀⠀⢀⣠⢶⡇⠀⠀⢰⡀⠀⠀⠀⠀⠀⡇⠀⠀
⢰⠇⡄⠀⠀⠀⡿⢣⣀⣀⣀⡤⠴⡞⠉⠀⢸⠀⠀⠀⣿⡇⠀⠀⠀⠀⠀⣧⠀⠀
⣸⠀⡇⠀⠀⠀⠀⠀⠀⠉⠀⠀⠀⢹⠀⠀⢸⠀⠀⢀⣿⠇⠀⠀⠀⠁⠀⢸⠀⠀
⣿⠀⡇⠀⠀⠀⠀⠀⢀⡤⠤⠶⠶⠾⠤⠄⢸⠀⡀⠸⣿⣀⠀⠀⠀⠀⠀⠈⣇⠀
⡇⠀⡇⠀⠀⡀⠀⡴⠋⠀⠀⠀⠀⠀⠀⠀⠸⡌⣵⡀⢳⡇⠀⠀⠀⠀⠀⠀⢹⡀
⡇⠀⠇⠀⠀⡇⡸⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠙⠮⢧⣀⣻⢂⠀⠀⠀⠀⠀⠀⢧
⣇⠀⢠⠀⠀⢳⠇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⡎⣆⠀⠀⠀⠀⠀⠘
⢻⠀⠈⠰⠀⢸⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠰⠘⢮⣧⡀⠀⠀⠀⠀
⠸⡆⠀⠀⠇⣾⠀⠀⠀⠀⠀⠀⠀⠀⠀⢠⠆⠀⠀⠀⠀⠀⠀⠀⠙⠳⣄⡀⢢⡀
<3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3
*/
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
220 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
5 ms |
340 KB |
Output is correct |
6 |
Correct |
23 ms |
468 KB |
Output is correct |
7 |
Correct |
105 ms |
1688 KB |
Output is correct |
8 |
Correct |
254 ms |
2580 KB |
Output is correct |
9 |
Correct |
434 ms |
4524 KB |
Output is correct |
10 |
Correct |
239 ms |
2420 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
220 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
5 ms |
340 KB |
Output is correct |
6 |
Correct |
23 ms |
468 KB |
Output is correct |
7 |
Correct |
105 ms |
1688 KB |
Output is correct |
8 |
Correct |
254 ms |
2580 KB |
Output is correct |
9 |
Correct |
434 ms |
4524 KB |
Output is correct |
10 |
Correct |
239 ms |
2420 KB |
Output is correct |
11 |
Correct |
0 ms |
212 KB |
Output is correct |
12 |
Correct |
55 ms |
704 KB |
Output is correct |
13 |
Correct |
47 ms |
692 KB |
Output is correct |
14 |
Correct |
42 ms |
792 KB |
Output is correct |
15 |
Correct |
267 ms |
2488 KB |
Output is correct |
16 |
Correct |
252 ms |
2372 KB |
Output is correct |
17 |
Correct |
223 ms |
2272 KB |
Output is correct |
18 |
Correct |
549 ms |
4560 KB |
Output is correct |
19 |
Correct |
524 ms |
4408 KB |
Output is correct |
20 |
Correct |
458 ms |
4348 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
212 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
0 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
10 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
212 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
0 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
10 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
212 KB |
Output is correct |
2 |
Correct |
1 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
1 ms |
212 KB |
Output is correct |
5 |
Correct |
0 ms |
212 KB |
Output is correct |
6 |
Correct |
1 ms |
212 KB |
Output is correct |
7 |
Correct |
0 ms |
212 KB |
Output is correct |
8 |
Correct |
0 ms |
212 KB |
Output is correct |
9 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
10 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
612 ms |
4324 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
0 ms |
220 KB |
Output is correct |
2 |
Correct |
0 ms |
212 KB |
Output is correct |
3 |
Correct |
1 ms |
212 KB |
Output is correct |
4 |
Correct |
0 ms |
212 KB |
Output is correct |
5 |
Correct |
5 ms |
340 KB |
Output is correct |
6 |
Correct |
23 ms |
468 KB |
Output is correct |
7 |
Correct |
105 ms |
1688 KB |
Output is correct |
8 |
Correct |
254 ms |
2580 KB |
Output is correct |
9 |
Correct |
434 ms |
4524 KB |
Output is correct |
10 |
Correct |
239 ms |
2420 KB |
Output is correct |
11 |
Correct |
0 ms |
212 KB |
Output is correct |
12 |
Correct |
55 ms |
704 KB |
Output is correct |
13 |
Correct |
47 ms |
692 KB |
Output is correct |
14 |
Correct |
42 ms |
792 KB |
Output is correct |
15 |
Correct |
267 ms |
2488 KB |
Output is correct |
16 |
Correct |
252 ms |
2372 KB |
Output is correct |
17 |
Correct |
223 ms |
2272 KB |
Output is correct |
18 |
Correct |
549 ms |
4560 KB |
Output is correct |
19 |
Correct |
524 ms |
4408 KB |
Output is correct |
20 |
Correct |
458 ms |
4348 KB |
Output is correct |
21 |
Correct |
0 ms |
212 KB |
Output is correct |
22 |
Correct |
1 ms |
212 KB |
Output is correct |
23 |
Correct |
1 ms |
212 KB |
Output is correct |
24 |
Correct |
1 ms |
212 KB |
Output is correct |
25 |
Correct |
0 ms |
212 KB |
Output is correct |
26 |
Correct |
1 ms |
212 KB |
Output is correct |
27 |
Correct |
0 ms |
212 KB |
Output is correct |
28 |
Correct |
0 ms |
212 KB |
Output is correct |
29 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
30 |
Halted |
0 ms |
0 KB |
- |