POJ-2387 Til the Cows Come Home ( 最短路 )

 1 #include<iostream>
 2 #include<algorithm>
 3 #include<cmath>
 4 #include<cstring>
 5 #include<stack>
 6 #include<queue>
 7 
 8 using namespace std;
 9 
10 int way[1005][1005];
11 bool flag[1005];
12 int main(){
13     ios::sync_with_stdio( false );
14 
15     int n, m;
16     
17     while( cin >> m >> n ){
18         int x, y, d;
19         memset( way, 0x3f3f3f3f, sizeof( way ) );
20         memset( flag, false, sizeof( flag ) );
21         for( int i = 0; i < m; i++ ){
22             cin >> x >> y >> d;
23             way[x][y] = way[y][x] = min( way[x][y], d );
24         }
25 
26         for( int k = 0; k < n - 1; k++ ){
27             int minv = 0x3f3f3f3f, mini;
28 
29             for( int i = 1; i < n; i++ ){
30                 if( !flag[i] && minv > way[n][i] ){
31                     minv = way[n][i];
32                     mini = i;
33                 }
34             }
35 
36             flag[mini] = true;
37             for( int i = 1; i < n; i++ ){
38                 if( !flag[i] ){
39                     way[n][i] = min( way[n][i], way[n][mini] + way[mini][i] );
40                 }
41             }
42         }
43 
44         cout << way[n][1] << endl;
45     }
46 
47     return 0;
48 }