Dijkstra's Shortest Path

dijkstra.cpp

int findNearest( int distances[], bool spt_flags[] )
{
    auto min_value = numeric_limits< int >::max(), min_index = 0;
    
    for ( auto v = 0; v < N; v++ )
    {
        auto not_in_spt = ( ! spt_flags[ v ] );
        auto closer = ( distances[ v ] < min_value );
        
        if ( not_in_spt && closer )
        {
            min_value = distances[ v ],
            min_index = v;
        }
    }
    
    return min_index;
}

void findShortestPaths( int graph[ N ][ N ], int source )
{
    auto distances = new int [ N ];
    auto spt_flags = new bool [ N ];
    
    for ( auto i = 0; i < N; i++ )
    {
        distances[ i ] = numeric_limits< int >::max(),
        spt_flags[ i ] = false;
    }
    
    distances[ source ] = 0;
    
    for ( auto count = 0; count < ( N - 1 ); count++ )
    {
        auto u = findNearest( distances, spt_flags );
        
        spt_flags[ u ] = true;
        
        for ( auto v = 0; v < N; v++ )
        {
            auto not_in_spt = ( ! spt_flags[ v ] );
            auto connected = ( graph[ u ][ v ] > 0 );
            auto initialized = ( distances[ u ] < numeric_limits< int >::max() );
            
            if ( not_in_spt && connected && initialized )
            {
                distances[ v ] = min( distances[ v ], distances[ u ] + graph[ u ][ v ] );
            }
        }
    }
    
    // 'distances' will contain all the shortest paths from 'source' to other vertices.
  
    delete [] spt_flags;
    delete [] distances;
}