最短路径

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int N, M, map[1010][1010], dis[1010], hash[1010], cnt, dp[1010];
const int inf = 0x7fffffff;
void Dijsktra () {
     dis[2] = 0;
     for ( int i = 1; i <= N; i++ ) {
          int pos, t = inf;
          for ( int j = 1; j <= N; j++ ) {
                 if ( hash[j] == 0 ) {
                     if ( dis[j] < t ) {
                         t = dis[j]; pos = j;    
                     }    
                 }   
          }   
          hash[pos] = 1;
          for ( int j = 1; j <= N; j++ ) {
                 if ( hash[j] == 0 ) {
                     if ( map[pos][j] != inf && dis[j] > dis[pos] + map[pos][j] ) {
                           dis[j] = dis[pos] + map[pos][j];    
                     }    
                 }   
          }
     }
}

int DFS ( int x ) {
     if ( x == 2  ) {
          cnt++; return 1;    
     }        
     if ( dp[x]  ) {
          cnt++; return dp[x];    
     }
    
     for ( int i = 1; i <= N; i++ ) {
          if ( hash[i] == 0  ) {
              if ( map[x][i] != inf &&dis[i] < dis[x] )  {
                      hash[i] = 1;
                      dp[x] += DFS ( i );
                      hash[i] = 0;   
              }   
          }   
     }
     return dp[x];
}

int main () {
     while ( scanf ( "%d", &N ), N ) {
           scanf ( "%d", &M );
           int x, y, val;
           for ( int i = 1; i <= N; i++ ) {
                dis[i] = inf ; hash[i] = 0;
                for ( int j = 1; j <= N; j++ )
                     map[i][j] = inf;  
           } 
           for ( int i = 1; i <= M; i++ ) {
                scanf ( "%d%d%d", &x, &y, &val );
                if ( map[x][y] > val )  {
                    map[x][y] = map[y][x] = val;    
                }
           }
           Dijsktra ();
           cnt = 0;
           memset ( hash, 0, sizeof (hash) );
           memset ( dp, 0, sizeof (dp) );
           DFS (1)
           printf ( "%d\n",  cnt );
     }
     return 0;  
}

 

////////////////////////

 

#include<stdio.h>
#include<string.h>
int map[110][110],dis[110], hash[110], N, M, x, y, v;
const int inf = 0x7fffffff;
int iii = 0x7f7f7f7f;
int Dijkstra () {
    for ( int i = 1; i <= N; ++ i ) {
        dis[i] = inf;
        hash[i] = 0;
    }
    dis[1] = 0;
    for ( int i = 1; i <= N; ++ i ) {
        int t = inf, pos = 0;
        for ( int j = 1; j <= N; ++ j ) {
            if ( !hash[j] ) {
                if ( dis[j] < t ) {
                     t = dis[j];
                     pos = j;   
                }    
            }    
        }  
        hash[pos] = 1;
        //if ( pos == N ) break;
        for ( int j = 1; j <= N; ++ j ) {
            if ( !hash[j] && map[pos][j] != inf ) {
               if ( dis[j] > dis[pos] + map[pos][j] ) {
                    dis[j] = dis[pos] + map[pos][j];   
               }     
            }    
        }  
    }    
    return dis[N];
}
int main( )
{
    while ( scanf ( "%d%d", &N, &M ) , N || M ) {
          for ( int i= 1; i <= N; ++ i ) {
              for ( int j = 1; j <= N; ++ j ) map[i][j] = inf;    
          }      
         // memset ( map, 0x7f, sizeof ( map ) );
         for ( int i = 1; i <= M ; ++ i ) {
             scanf ( "%d%d%d", &x, &y, &v );
             map[x][y] = map[y][x] = v;    
         }   
         printf ( "%d\n", Dijkstra () );
    }
    return 0;
}