By yusijia

Updated:

Contents 
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 <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <cmath>
#define MAXN 10010
#define INF 0x3f3f3f3f
using namespace std;
int n, pp;
double ans;
int ranks[105], father[105];

struct node{  //存小岛的坐标
    int x;
    int y;
}node[105];

struct Edge{
    int xx;
    int yy;
    double juli;
}edge[MAXN];    //边最多有n * (n - 1) / 2条

bool cmp(Edge e1, Edge e2){
    return e1.juli < e2.juli ? 1 : -1; //注意这里是double的
}

void init_set()
{
    for(int i = 0; i <= n; i++){
        father[i] = i;
        ranks[i] = 1;
    }
}

int find_set(int x)
{
    return x == father[x] ? father[x] : father[x] = find_set(father[x]);
}

void union_set(int x, int y)
{
    if(ranks[x] >= ranks[y]){
        ranks[x] += ranks[y];
        father[y] = x;
    }
    else{
        ranks[y] += ranks[x];
        father[x] = y;
    }
}

double distances(int x1, int y1, int x2, int y2)
{
    double t = double((x1 - x2)*(x1 - x2) + (y1 - y2)*(y1 - y2));
    return sqrt(t);
}

double kruskal()
{
    ans = 0.0;
    //int N = n*(n - 1)/2;
    sort(edge, edge + pp, cmp);
    for(int i = 0; i < pp; i++){
        int root_x = find_set(edge[i].xx);
        int root_y = find_set(edge[i].yy);
        if(root_x != root_y && edge[i].juli != INF){//如果未连通且距离不是无限远
            ans += edge[i].juli;
            union_set(root_x, root_y);
        }
    }
    return ans;
}

int main()
{
    freopen("input.txt", "r", stdin);
    int T;
    scanf("%d", &T);
    while(T--){
        scanf("%d", &n);
        init_set();
        if(n == 1 || n == 0) {printf("oh!\n"); continue;}
        for(int i = 0; i < n; i++){
            scanf("%d%d", &node[i].x, &node[i].y);
        }
        double dis;
        pp = 0;
        for(int i = 0; i < n; i++){
            for(int j = i + 1; j < n; j++){
                dis = distances(node[i].x, node[i].y, node[j].x, node[j].y);
                if(dis < 10 || dis > 1000){
                    edge[i].xx = i;
                    edge[i].yy = j;
                    edge[i].juli = INF;
                }
                else{
                    edge[i].xx = i;
                    edge[i].yy = j;
                    edge[i].juli = dis;
                }
                pp++;
            }
        }
        double cost = kruskal() * 100;
        int flag = find_set(edge[2].xx);
        if(ranks[flag] != n)
            printf("oh!\n");
        else{
            printf("%.1f\n", cost);
        }
    }
    return 0;
}
Contents