最短路 HDU - 2544 (dijkstra算法或Floyd算法)

Dijkstra解法：

 #include <stdio.h>
 #include <iostream>
 #include <cstring>
 #include <vector>
 #include <algorithm>
 #include <sstream>

 #define INF 1000000000

 using namespace std;
 int N, M;
 int dist[],g[][];
 int vis[];

 void dijkstra(int start)
 {
     for(int i=;i<=N;i++)
         dist[i]=INF;
     dist[start] = ;
     memset(vis,,sizeof(vis));

     while()
     {
         int mark=-,mindis=INF;
         for(int i=;i<=N;i++)
         {
             if(!vis[i]&&dist[i]<mindis)
             {
                 mindis=dist[i];
                 mark=i;
             }
         }
         if(mindis == INF)    // 找不到未收录的节点，则说明算法结束，退出
             break;
         vis[mark]=;

         for(int i=;i<=N;i++)
         {
             if(!vis[i])
             {
                 dist[i]=min(dist[i],dist[mark]+g[mark][i]);
             }
         }
     }
 }

 int main()
 {
     while(cin >> N >> M)
     {
         if(N ==  && M == )
             break;

         for(int i = ; i <= N; ++i)
             for(int j = ; j <= N; ++j)
             {
                 if(i == j)
                     g[i][j] = ;
                 else
                     g[i][j] = INF;
             }

         for(int i = ; i <= M; ++i)
         {
             int a,b,c;
             cin >> a >> b >> c;
             g[a][b] = g[b][a] = c;
         }

         dijkstra();
         cout << dist[N] << endl; 

     } 

     return ;
 }

Floyd解法:

 #include <stdio.h>
 #include <iostream>
 #include <string>
 #include <vector>
 #include <algorithm>
 #include <sstream>

 using namespace std;

 int dis[][];

 int main()
 {
        int N, M;
     while(cin >> N >> M)
     {
         if(N ==  && M == )
             break;

         for(int i = ; i <= N; ++i)
         {
             for(int j = ; j <= N; ++j)
             {
                 if(i == j)
                     dis[i][j] = ;
                 else
                     dis[i][j] = ;
             }
         }

         int a, b, c;
         for(int i = ; i <= M; ++i)
         {
             cin >> a >> b >> c;
             if(dis[a][b] > c)
                 dis[a][b] = dis[b][a] = c;

         }

         for(int k = ; k <= N; ++k)
             for(int i = ; i <= N; ++i)
                 for(int j = ; j <= N; ++j)
                 {
                     if(dis[i][j] > dis[i][k] + dis[k][j])
                         dis[i][j] = dis[i][k] + dis[k][j];
                 }

         cout << dis[][N] << endl;
     } 

     return ;
 }