1 int n;
2 int weight;
3 int g[MAXN][MAXN];
4 int vis[MAXN];
5 int dis[MAXN];
6
7
8 void prim(int v0){
9 int pos = v0;
10 for(int i = 1; i <= n; i++){
11 dis[i] = g[v0][i];
12 }
13 vis[pos] = 1;
14 for(int i = 1; i < n; i++){
15 int mins = INF;
16 for(int j = 1; j <= n; j++){
17 if(!vis[j] && dis[j] < mins){
18 pos = j;
19 mins = dis[j];
20 }
21 }
22 weight += mins;
23 vis[pos] = 1;
24 for(int j = 1; j <= n; j++){
25 if(!vis[j] && g[pos][j] < dis[j]){
26 dis[j] = g[pos][j];
27 }
28 }
29 }
30 }
1 #include <iostream>
2 #include <queue>
3 #include <string.h>
4 using namespace std;
5 #define M 1000
6 int g[M][M];
7 int n, cnt;
8 int node[M];
9 int weight;
10
11 void init(){
12 memset(g,0,sizeof(g));
13 memset(node,0,sizeof(node));
14 }
15
16 struct Edge{
17 int from,to,w;
18 };
19
20 bool operator < (const Edge &a, const Edge &b){
21 return a.w > b.w;
22 }
23
24 int prim(int start){
25 node[start] = 1;
26 priority_queue<Edge> q;
27 for(int i = 0; i < n; i++){
28 if(0 != g[start][i]){
29 Edge e;
30 e.from = start;
31 e.to = i;
32 e.w = g[start][i];
33 q.push(e);
34 }
35 }
36 while(!q.empty()){
37 Edge cmp = q.top();
38 q.pop();
39 if(node[cmp.from] == 0 || node[cmp.to] == 0){
40 node[cmp.from] = node[cmp.to] = 1;
41 weight += cmp.w;
42 }
43 for(int i = 0; i < n; i++){
44 if(node[i] == 0 && g[cmp.to][i] != 0){
45 Edge add;
46 add.from = cmp.to;
47 add.to = i;
48 add.w = g[cmp.to][i];
49 q.push(add);
50 }
51 }
52 }
53 }
54 int main(){
55 init();
56 cin >> n >> cnt;
57 for(int i = 0; i < cnt; i++){
58 int a, b, w;
59 cin >> a >> b >> w;
60 g[a][b] = g[b][a] = w;
61 }
62 prim(0);
63 cout << weight << endl;
64 return 0;
65 }
