|
2 | 2 |
|
3 | 3 |
|
4 | 4 | class Graph:
|
5 |
| - def __init__(self, matrix_size: int = 10): |
6 |
| - self._matrix_size: int = matrix_size |
7 |
| - self._vertices: list = [None] * self._matrix_size |
8 |
| - self._pointer: int = 0 |
9 |
| - self._adjacency_matrix: list = [[None for i in range(self._matrix_size)] for j in range(self._matrix_size)] |
10 |
| - self._prev: dict = {} |
11 |
| - self._visited: dict = {} |
12 |
| - |
13 |
| - def add_vertex(self, label: str = None, weight: int = float("inf")): |
14 |
| - if self._pointer == self._matrix_size: |
| 5 | + def __init__(self, size: int = 10): |
| 6 | + self.size: int = size |
| 7 | + self.index: int = 0 |
| 8 | + self.vertices_list: list = [None] * self.size |
| 9 | + self.vertices: dict = {} |
| 10 | + self.adjacency_matrix: list = [[None for i in range(self.size)] for j in range(self.size)] |
| 11 | + self.prev: dict = {} |
| 12 | + self.visited: dict = {} |
| 13 | + |
| 14 | + def add_vertex(self, label: str): |
| 15 | + if self.index == self.size: # matrix is full |
15 | 16 | return
|
16 |
| - vertex: Vertex = Vertex(label, float("inf"), self._pointer) |
17 |
| - self._vertices[self._pointer] = vertex |
18 |
| - self._prev[label] = None |
19 |
| - self._pointer += 1 |
| 17 | + vertex: Vertex = Vertex(label, float("inf"), self.index) |
| 18 | + self.vertices_list[self.index] = vertex |
| 19 | + self.vertices[vertex.label] = vertex |
| 20 | + self.index += 1 |
| 21 | + self.prev[vertex.label] = None |
| 22 | + self.visited[vertex.label] = False |
20 | 23 |
|
21 | 24 | def add_edge(self, label1: str, label2: str, weight: int):
|
22 |
| - vertex1: Vertex = self._find_vertex_by_label(label1) |
23 |
| - vertex2: Vertex = self._find_vertex_by_label(label2) |
24 |
| - self._adjacency_matrix[vertex1.get_index()][vertex2.get_index()] = weight |
| 25 | + index1: int = self.vertices[label1].index |
| 26 | + index2: int = self.vertices[label2].index |
| 27 | + self.adjacency_matrix[index1][index2] = weight |
25 | 28 |
|
26 | 29 | def dijkstra(self, label: str):
|
27 |
| - vertex: Vertex = self._find_vertex_by_label(label) |
28 |
| - vertex.set_weight(0) |
29 |
| - while vertex is not None: |
30 |
| - index: int = vertex.get_index() |
31 |
| - for i in range(len(self._adjacency_matrix[index])): |
32 |
| - if self._adjacency_matrix[index][i] is not None: |
33 |
| - neighbour: Vertex = self._vertices[i] |
34 |
| - if neighbour.get_weight() > vertex.get_weight() + self._adjacency_matrix[index][i]: |
35 |
| - self._prev[neighbour.get_label()] = vertex.get_label() |
36 |
| - neighbour.set_weight(vertex.get_weight() + self._adjacency_matrix[index][i]) |
37 |
| - self._visited[vertex.get_label()] = vertex |
38 |
| - vertex = self._find_minimum_weight_vertex() |
39 |
| - |
40 |
| - def return_path(self, end_label: str = None) -> str: |
41 |
| - if self._prev[end_label] is None: |
42 |
| - return end_label |
| 30 | + current_vertex: Vertex = self.vertices[label] |
| 31 | + current_vertex.weight = 0 |
| 32 | + while current_vertex is not None: |
| 33 | + self.visited[current_vertex.label] = True |
| 34 | + for i in range(self.index): |
| 35 | + if self.adjacency_matrix[current_vertex.index][i] is not None: |
| 36 | + weight: int = self.adjacency_matrix[current_vertex.index][i] |
| 37 | + neighbour: Vertex = self.vertices_list[i] |
| 38 | + if current_vertex.weight + weight < neighbour.weight: |
| 39 | + neighbour.weight = current_vertex.weight + weight |
| 40 | + self.prev[neighbour.label] = current_vertex.label |
| 41 | + current_vertex = self.find_minimum_weight_vertex() |
| 42 | + |
| 43 | + def return_path(self, label: str) -> str: |
| 44 | + if self.prev[label] is None: |
| 45 | + return label |
43 | 46 | else:
|
44 |
| - return self.return_path(self._prev[end_label]) + " -> " + end_label |
45 |
| - |
46 |
| - def _find_vertex_by_label(self, label: str) -> Vertex: |
47 |
| - vertex: Vertex = None |
48 |
| - i: int = 0 |
49 |
| - found: bool = False |
50 |
| - while i <= self._pointer and not found: |
51 |
| - if self._vertices[i].get_label() == label: |
52 |
| - vertex = self._vertices[i] |
53 |
| - found = True |
54 |
| - else: |
55 |
| - i += 1 |
56 |
| - return vertex |
| 47 | + return self.return_path(self.prev[label]) + " -> " + label |
57 | 48 |
|
58 |
| - def _find_minimum_weight_vertex(self): |
| 49 | + def find_minimum_weight_vertex(self): |
59 | 50 | vertex: Vertex = None
|
60 |
| - for i in range(0, self._pointer, +1): |
61 |
| - v: Vertex = self._vertices[i] |
62 |
| - if v.get_label() not in self._visited: |
| 51 | + for label in self.vertices: |
| 52 | + if not self.visited[label]: |
63 | 53 | if vertex is None:
|
64 |
| - vertex = v |
65 |
| - elif vertex.get_weight() > v.get_weight(): |
66 |
| - vertex = v |
| 54 | + vertex = self.vertices[label] |
| 55 | + else: |
| 56 | + if vertex.weight > self.vertices[label].weight: |
| 57 | + vertex = self.vertices[label] |
67 | 58 | return vertex
|
| 59 | + |
| 60 | + |
| 61 | + |
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