nbro

## double_bridge.md

      
        
          
            
              
              1 file
            
          
          
            
              
              0 forks
            
          
          
            
              
              0 comments
            
          
          
            
              
              0 stars
            
          
        
        
          
              
          
          
            
                nbro
                / double_bridge.md
            
            
              Last active
              March 12, 2017 22:41
            
              
                In-place double-bridge or 4-opt move
              
          
        
      
        
  
      
    I've implemented a double-bridge (or 4-opt) move in place, i.e. without any additional containers than the original. I'm sharing it with you first because I would like to know if it's correct or if I can improve it and second because I thought it could be helpful to someone else (since I have not found anything on the web).
/*
 * DOUBLE-BRIDGE-COMPUTE-GAIN
 *
 * Computes and returns the gain of a random double-bridge move.
 * The indices of the vertices used are also returnd as 2nd, 3rd and 4th parametrs of the array returned.
 * */
std::array<int, 4> double_bridge_in_place_compute_gain(const MatrixGraph &m, const VectorTour &t) {