POJ 1258 Agri-Net

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <stack>
13 #define LL long long
14 #define pii pair<int,int>
15 #define INF 0x3f3f3f3f
16 using namespace std;
17 const int maxn = 10000;
18 struct arc{
19     int u,v,w;
20     arc(int x = 0,int y = 0,int z = 0){
21         u = x;
22         v = y;
23         w = z;
24     }
25 };
26 arc e[maxn];
27 int uf[maxn],n,m;
28 int Find(int x){
29     if(x != uf[x])
30         uf[x] = Find(uf[x]);
31     return uf[x];
32 }
33 bool cmp(const arc &x,const arc &y){
34     return x.w < y.w;
35 }
36 int kruskal(){
37     for(int i = 0; i <= n; i++) uf[i] = i;
38     sort(e,e+m,cmp);
39     int sum = 0;
40     for(int i = 0; i < m; i++){
41         int tx = Find(e[i].u);
42         int ty = Find(e[i].v);
43         if(tx != ty){
44             sum += e[i].w;
45             uf[tx] = ty;
46         }
47     }
48     return sum;
49 }
50 int main() {
51     int i,j,w,u,v;
52     while(~scanf("%d",&n)){
53         for(m = i = 0; i < n; i++){
54             for(j = 0; j < n; j++){
55                 scanf("%d",&w);
56                 if(j > i) e[m++] = arc(i+1,j+1,w);
57             }
58         }
59         printf("%d\n",kruskal());
60     }
61     return 0;
62 }

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #include <stack>
13 #define LL long long
14 #define pii pair<int,int>
15 #define INF 0x3f3f3f3f
16 using namespace std;
17 const int maxn = 10000;
18 struct arc {
19     int to,w;
20     arc(int x = 0,int y = 0) {
21         to = x;
22         w = y;
23     }
24 };
25 vector<arc>g[maxn];
26 priority_queue< pii, vector< pii >,greater< pii > >q;
27 int n,d[maxn];
28 bool done[maxn];
29 int prim(){
30     for(int i = 0; i <= n; i++){
31         d[i] = INF;
32         done[i] = false;
33     }
34     int ans = d[1] = 0;
35     while(!q.empty()) q.pop();
36     q.push(make_pair(d[1],1));
37     while(!q.empty()){
38         int u = q.top().second;
39         int w = q.top().first;
40         q.pop();
41         if(done[u]) continue;
42         done[u] = true;
43         ans += w;
44         for(int i = 0; i < g[u].size(); i++){
45             if(d[g[u][i].to] > g[u][i].w){
46                 d[g[u][i].to] = g[u][i].w;
47                 q.push(make_pair(g[u][i].w,g[u][i].to));
48             }
49         }
50     }
51     return ans;
52 }
53 int main() {
54     int i,j,w;
55     while(~scanf("%d",&n)) {
56         for(i = 0; i <= n; i++) g[i].clear();
57         for(i = 1; i <= n; i++) {
58             for(j = 1; j <= n; j++) {
59                 scanf("%d",&w);
60                 if(i != j) g[i].push_back(arc(j,w));
61             }
62         }
63         printf("%d\n",prim());
64     }
65     return 0;
66 }