| 9 | |
| 10 | |
| 11 | class Node: |
| 12 | |
| 13 | def __init__(self, key): |
| 14 | self.key = key |
| 15 | self.visit_state = State.unvisited |
| 16 | self.incoming_edges = 0 |
| 17 | self.adj_nodes = {} # Key = key, val = Node |
| 18 | self.adj_weights = {} # Key = key, val = weight |
| 19 | |
| 20 | def __repr__(self): |
| 21 | return str(self.key) |
| 22 | |
| 23 | def __lt__(self, other): |
| 24 | return self.key < other.key |
| 25 | |
| 26 | def add_neighbor(self, neighbor, weight=0): |
| 27 | if neighbor is None or weight is None: |
| 28 | raise TypeError('neighbor or weight cannot be None') |
| 29 | neighbor.incoming_edges += 1 |
| 30 | self.adj_weights[neighbor.key] = weight |
| 31 | self.adj_nodes[neighbor.key] = neighbor |
| 32 | |
| 33 | def remove_neighbor(self, neighbor): |
| 34 | if neighbor is None: |
| 35 | raise TypeError('neighbor cannot be None') |
| 36 | if neighbor.key not in self.adj_nodes: |
| 37 | raise KeyError('neighbor not found') |
| 38 | neighbor.incoming_edges -= 1 |
| 39 | del self.adj_weights[neighbor.key] |
| 40 | del self.adj_nodes[neighbor.key] |
| 41 | |
| 42 | |
| 43 | class Graph: |