poj 2485 Highways

 1 #include<iostream>
 2 #include<queue>
 3 #include<cstdio>
 4 #include<cstring>
 5 #include<cmath>
 6 #include<algorithm>
 7 using namespace std;
 8 #define size 500
 9 #define inf 999999999
10 int m[size+5][size+5];
11 int lowcost[size+5];
12 /*struct cmp{
13     operator bool(int a,int b){
14     return lowcost[a]> lowcost[b];                                      
15 }
16 }; */
17 void prime(int n){
18     int i=0,j;
19     int k=0;
20     //priority_queue<int, vector<int>,cmp> q;    
21     lowcost[0]=0; 
22     for(i=1;i<n;i++){
23         lowcost[i]=m[0][i];
24         //q.push(lowcost[i]);
25     }                
26     int max=0;          
27     for(i=1;i<n;i++){
28         int min=inf;
29         for(j=1;j<n;j++){
30             if(lowcost[j]&&lowcost[j]<min){
31                 min=lowcost[j];
32                 k=j;
33             }
34         }
35         if(min>max){
36             max=min;
37         }
38         //cout<<"i:  "<<lowcost[i]<<endl;
39         for(j=1;j<n;j++){
40             if(lowcost[j]>m[k][j]){
41                 lowcost[j]=m[k][j];
42             }
43         }
44         lowcost[k]=0;
45     }
46     /*for(i=0;i<n;i++)
47     cout<<lowcost[i]<<endl;*/
48     cout<<max<<endl;
49 }
50 int main(){
51     int n;
52     scanf("%d",&n);
53     while(n--){
54         int i,j,s;
55         scanf("%d",&s);
56         for(i=0;i<s;i++){
57             for(j=0;j<s;j++){
58                 scanf("%d",&m[i][j]);
59             }
60         }
61         prime(s);
62     }
63     return 0;
64 }