Petru isi ia la revedere de la colegi si coboara la metrou.
A. Reteaua de metrou
Consulta harta statiilor. Reteaua de metrou contine mai multe statii, reprezentate in figura de mai jos prin cercuri.
Puteti completa harta prin trasarea tunelurilor?
Sursa: problema originală (Ruxandra F. Olimid)
Petru is saying goodbye to his colleagues and goes down in the underground.
A. The undergound
Petru sees map of the underground. The stations are represented in the figure below by circles.
1. Each station is marked with a number that represents the number of tunnels connected directly to the station
2. The tunnels begin and end in 2 different stations
3. The tunnels cannot intersect other tunnels
4. The tunnels are in a straight line, only vertical and horizontal (they cannot be diagonally, for example)
5. Between two stations can be up to 2 direct tunnels
6. From any station you can reach any other station (i.e. there are no inaccessible stations)
Can you complete the map by indicating the tunnels?
Source: original problem (Ruxandra F. Olimid)