kruskal_并查集_代码模板_hdu1232

kruskal代码模板

input

a b
v1 v2 w1
v2 v3 w2
...

a_the number of verteices

b_the number of edges

v1_verteices

wi_the weight of each edge

 1 #include<iostream>
 2 #include<string>
 3 #include<cstdio>
 4 #include<cstdlib>
 5 #include<cstring>
 6 #include<cmath>
 7 #include<ctype.h>
 8 #include<algorithm>
 9 #include<map>
10 #include<vector>
11 #include<set>
12 
13 #define MAX 100005
14 #define MOD 1000003
15 #define inf 100000000
16 #define eps 1e-9
17 #define pi acos(-1.0)
18 #define LL long long 
19 #define I64 __int64
20 #define max(a, b) ((a) > (b) ? (a) : (b))
21 #define min(a, b) ((a) < (b) ? (a) : (b))
22 
23 using namespace std;
24 
25 struct edge {
26     int v1, v2, w;
27 };
28 
29 int edge_num, vertex_num;
30 edge volume_e[30];
31 int father[30];
32 
33 int cmp(edge a, edge b) {
34     return a.w < b.w;
35 }
36 
37 int find(int x) {
38     int root = x;
39     if(father[root] != root)
40         root = father[root];
41     return root;
42 }
43 
44 int judge(edge e) {
45     if(find(e.v1) != find(e.v2))
46         return 1;
47     return 0;
48 
49 }
50 int main()
51 {
52     freopen("in.txt", "r", stdin);
53     cin >> edge_num >> vertex_num;// the number of edge and vertex
54     // v1, v2, weight
55     for(int i = 0; i < edge_num; i++)
56         scanf("%d %d %d", &volume_e[i].v1, &volume_e[i].v2, &volume_e[i].w);
57 
58     // initial
59     for(int i = 1; i <= vertex_num; i++) father[i] = i;
60 
61     sort(volume_e, volume_e+edge_num, cmp);
62 
63     int sum = 0;
64     for (int i = 0;i < edge_num;i ++)
65     {
66         int x = find (volume_e[i].v1);
67         int y = find (volume_e[i].v2);
68         if (x != y)
69         {
70             sum += volume_e[i].w;
71             father[x] = y;
72         }
73     }
74     printf ("%d\n", sum);
75 }
76 
77 /*
78 5 5
79 1 2 2
80 2 3 3
81 1 4 1
82 3 4 2
83 4 5 4
84 
85 */

hdu1232

 1 using namespace std;
 2 
 3 int add;
 4 int f[100010];
 5 int n, m;
 6 
 7 int findset(int x)
 8 {
 9     int set = x;
10     while(f[set] != set)
11     {
12         set = f[set];
13     }
14     return set;
15 }
16 
17 void merge(int a, int b)
18 {
19     int x = findset(a);
20     int y = findset(b);
21     if(x != y)
22         f[x] = y;
23 }
24 
25 int main()
26 {
27     freopen("in.txt", "r", stdin);
28     while(scanf("%d %d", &n, &m) == 2)
29     {
30         add = 0;
31         if(n == 0)
32             break;
33         else if(m == 0)
34         {
35             add = n - 1;
36             printf("%d\n", add);
37         }
38         else
39         {
40             for(int i = 1; i <= n; i++) f[i] = i;
41 
42             for(int i = 0; i < m; i++)
43             {
44                 int a, b;
45                 scanf("%d %d", &a, &b);
46                 merge(a, b);
47             }
48 
49             for(int i = 1; i <= n; i++)
50                 if(f[i] == i)
51                     add++;
52             add--;
53             printf("%d\n", add);
54         }
55         //
56         memset(f, 0, sizeof(f));
57     }
58 }
59 
60 /*
61 4 2
62 1 3
63 4 3
64 3 3
65 1 2
66 1 3
67 2 3
68 5 2
69 1 2
70 3 5
71 999 0
72 0
73 
74 */

 

 

转载于:https://www.cnblogs.com/shichuanwang/archive/2012/08/26/2657418.html