Floyd-Warshall's Algorithm.c

Graph floyd_warshall( Graph g ) {
   int i, j, k, N = g.size;
   Graph spg; // All-Pairs Shortest path graph
 
   for ( i = 0; i < N; i++ )
      for ( j = 0; j < N; j++ )
         set_edge_weight( spg, i, j, edge_weight( g, i, j ) );
 
   for ( k = 0; k < N; k++ )
      for ( i = 0; i < N; i++ )
         for ( j = 0; j < N; j++ )
            if ( edge_weight( spg, i, j ) > edge_weight( spg, i, k ) + edge_weight( spg, k, j ) )
               set_edge_weight( spg, i, j, edge_weight( spg, i, k ) + edge_weight( spg, k, j ) );
 
   return spg;
}

int dist[N][N];  // For some N
int i, j, k;
// Input data into dist, where dist[i][j] is the distance from i to j.
 
   for ( k = 0; k < N; k++ )
      for ( i = 0; i < N; i++ )
         for ( j = 0; j < N; j++ )
            dist[i][j] = min( dist[i][j], dist[i][k] + dist[k][j] );
 
// Now the shortest distance between i and j will be in dist[i][j].