blob: 167dc5c121c9436afe9b8e48d99ae1ae545297e3 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
|
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <cassert>
#include <vector>
#include <cmath>
using std::vector;
using std::pair;
struct Vertex
{
int a;
int b;
double l;
static int compare(Vertex &a, Vertex &b)
{
return (a.l < b.l);
}
void print()
{
std::cout << a << ";" << b << " " << l << std::endl;
}
};
struct Point
{
int x;
int y;
int parent;
void print()
{
std::cout << x << ";" << y << " " << parent << std::endl;
}
};
struct Points
{
vector<Point> points;
vector<Vertex> vertices;
Points(int n) : points(n), vertices(n*n) { }
void read(int i)
{
std::cin >> points[i].x >> points[i].y;
points[i].parent = i;
}
void print()
{
for (int i = 0; i < points.size(); i++)
points[i].print();
}
int find(int i)
{
if (points[i].parent == i)
return i;
points[i].parent = find(points[i].parent);
return points[i].parent;
}
double solve(int k)
{
int x = 0;
for (int i = 0; i < points.size(); i++) {
for (int j = i + 1; j < points.size(); j++) {
vertices[x].a = i;
vertices[x].b = j;
vertices[x].l = sqrt(
(points[i].x - points[j].x) * (points[i].x - points[j].x)
+
(points[i].y - points[j].y) * (points[i].y - points[j].y)
);
x += 1;
}
}
vertices.resize(x);
std::sort(vertices.begin(), vertices.end(), Vertex::compare);
int n = 0;
double result = 0.;
for (int i = 0; i < vertices.size(); i++) {
int realA = find(vertices[i].a);
int realB = find(vertices[i].b);
if (realA != realB) {
if (n == points.size() - k) {
result = vertices[i].l;
break;
}
n += 1;
points[realB].parent = realA;
}
}
return result;
}
};
int main() {
size_t n;
int k;
std::cin >> n;
Points points(n);
for (size_t i = 0; i < n; i++)
points.read(i);
std::cin >> k;
std::cout << std::setprecision(10) << points.solve(k) << std::endl;
}
|
