translation: Add Python and Java code for EN version (#1345)

* Add the intial translation of code of all the languages

* test

* revert

* Remove

* Add Python and Java code for EN version

en/codes/python/chapter_graph/graph_adjacency_list.py

@@ -0,0 +1,111 @@
+"""
+File: graph_adjacency_list.py
+Created Time: 2023-02-23
+Author: krahets (krahets@163.com)
+"""
+
+import sys
+from pathlib import Path
+
+sys.path.append(str(Path(__file__).parent.parent))
+from modules import Vertex, vals_to_vets
+
+
+class GraphAdjList:
+    """Undirected graph class based on adjacency list"""
+
+    def __init__(self, edges: list[list[Vertex]]):
+        """Constructor"""
+        # Adjacency list, key: vertex, value: all adjacent vertices of that vertex
+        self.adj_list = dict[Vertex, list[Vertex]]()
+        # Add all vertices and edges
+        for edge in edges:
+            self.add_vertex(edge[0])
+            self.add_vertex(edge[1])
+            self.add_edge(edge[0], edge[1])
+
+    def size(self) -> int:
+        """Get the number of vertices"""
+        return len(self.adj_list)
+
+    def add_edge(self, vet1: Vertex, vet2: Vertex):
+        """Add edge"""
+        if vet1 not in self.adj_list or vet2 not in self.adj_list or vet1 == vet2:
+            raise ValueError()
+        # Add edge vet1 - vet2
+        self.adj_list[vet1].append(vet2)
+        self.adj_list[vet2].append(vet1)
+
+    def remove_edge(self, vet1: Vertex, vet2: Vertex):
+        """Remove edge"""
+        if vet1 not in self.adj_list or vet2 not in self.adj_list or vet1 == vet2:
+            raise ValueError()
+        # Remove edge vet1 - vet2
+        self.adj_list[vet1].remove(vet2)
+        self.adj_list[vet2].remove(vet1)
+
+    def add_vertex(self, vet: Vertex):
+        """Add vertex"""
+        if vet in self.adj_list:
+            return
+        # Add a new linked list to the adjacency list
+        self.adj_list[vet] = []
+
+    def remove_vertex(self, vet: Vertex):
+        """Remove vertex"""
+        if vet not in self.adj_list:
+            raise ValueError()
+        # Remove the vertex vet's corresponding linked list from the adjacency list
+        self.adj_list.pop(vet)
+        # Traverse other vertices' linked lists, removing all edges containing vet
+        for vertex in self.adj_list:
+            if vet in self.adj_list[vertex]:
+                self.adj_list[vertex].remove(vet)
+
+    def print(self):
+        """Print the adjacency list"""
+        print("Adjacency list =")
+        for vertex in self.adj_list:
+            tmp = [v.val for v in self.adj_list[vertex]]
+            print(f"{vertex.val}: {tmp},")
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    # Initialize undirected graph
+    v = vals_to_vets([1, 3, 2, 5, 4])
+    edges = [
+        [v[0], v[1]],
+        [v[0], v[3]],
+        [v[1], v[2]],
+        [v[2], v[3]],
+        [v[2], v[4]],
+        [v[3], v[4]],
+    ]
+    graph = GraphAdjList(edges)
+    print("\nAfter initialization, the graph is")
+    graph.print()
+
+    # Add edge
+    # Vertices 1, 2 i.e., v[0], v[2]
+    graph.add_edge(v[0], v[2])
+    print("\nAfter adding edge 1-2, the graph is")
+    graph.print()
+
+    # Remove edge
+    # Vertices 1, 3 i.e., v[0], v[1]
+    graph.remove_edge(v[0], v[1])
+    print("\nAfter removing edge 1-3, the graph is")
+    graph.print()
+
+    # Add vertex
+    v5 = Vertex(6)
+    graph.add_vertex(v5)
+    print("\nAfter adding vertex 6, the graph is")
+    graph.print()
+
+    # Remove vertex
+    # Vertex 3 i.e., v[1]
+    graph.remove_vertex(v[1])
+    print("\nAfter removing vertex 3, the graph is")
+    graph.print()

en/codes/python/chapter_graph/graph_adjacency_matrix.py

@@ -0,0 +1,116 @@
+"""
+File: graph_adjacency_matrix.py
+Created Time: 2023-02-23
+Author: krahets (krahets@163.com)
+"""
+
+import sys
+from pathlib import Path
+
+sys.path.append(str(Path(__file__).parent.parent))
+from modules import Vertex, print_matrix
+
+
+class GraphAdjMat:
+    """Undirected graph class based on adjacency matrix"""
+
+    def __init__(self, vertices: list[int], edges: list[list[int]]):
+        """Constructor"""
+        # Vertex list, elements represent "vertex value", index represents "vertex index"
+        self.vertices: list[int] = []
+        # Adjacency matrix, row and column indices correspond to "vertex index"
+        self.adj_mat: list[list[int]] = []
+        # Add vertex
+        for val in vertices:
+            self.add_vertex(val)
+        # Add edge
+        # Please note, edges elements represent vertex indices, corresponding to vertices elements indices
+        for e in edges:
+            self.add_edge(e[0], e[1])
+
+    def size(self) -> int:
+        """Get the number of vertices"""
+        return len(self.vertices)
+
+    def add_vertex(self, val: int):
+        """Add vertex"""
+        n = self.size()
+        # Add new vertex value to the vertex list
+        self.vertices.append(val)
+        # Add a row to the adjacency matrix
+        new_row = [0] * n
+        self.adj_mat.append(new_row)
+        # Add a column to the adjacency matrix
+        for row in self.adj_mat:
+            row.append(0)
+
+    def remove_vertex(self, index: int):
+        """Remove vertex"""
+        if index >= self.size():
+            raise IndexError()
+        # Remove vertex at `index` from the vertex list
+        self.vertices.pop(index)
+        # Remove the row at `index` from the adjacency matrix
+        self.adj_mat.pop(index)
+        # Remove the column at `index` from the adjacency matrix
+        for row in self.adj_mat:
+            row.pop(index)
+
+    def add_edge(self, i: int, j: int):
+        """Add edge"""
+        # Parameters i, j correspond to vertices element indices
+        # Handle index out of bounds and equality
+        if i < 0 or j < 0 or i >= self.size() or j >= self.size() or i == j:
+            raise IndexError()
+        # In an undirected graph, the adjacency matrix is symmetric about the main diagonal, i.e., satisfies (i, j) == (j, i)
+        self.adj_mat[i][j] = 1
+        self.adj_mat[j][i] = 1
+
+    def remove_edge(self, i: int, j: int):
+        """Remove edge"""
+        # Parameters i, j correspond to vertices element indices
+        # Handle index out of bounds and equality
+        if i < 0 or j < 0 or i >= self.size() or j >= self.size() or i == j:
+            raise IndexError()
+        self.adj_mat[i][j] = 0
+        self.adj_mat[j][i] = 0
+
+    def print(self):
+        """Print adjacency matrix"""
+        print("Vertex list =", self.vertices)
+        print("Adjacency matrix =")
+        print_matrix(self.adj_mat)
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    # Initialize undirected graph
+    # Please note, edges elements represent vertex indices, corresponding to vertices elements indices
+    vertices = [1, 3, 2, 5, 4]
+    edges = [[0, 1], [0, 3], [1, 2], [2, 3], [2, 4], [3, 4]]
+    graph = GraphAdjMat(vertices, edges)
+    print("\nAfter initialization, the graph is")
+    graph.print()
+
+    # Add edge
+    # Indices of vertices 1, 2 are 0, 2 respectively
+    graph.add_edge(0, 2)
+    print("\nAfter adding edge 1-2, the graph is")
+    graph.print()
+
+    # Remove edge
+    # Indices of vertices 1, 3 are 0, 1 respectively
+    graph.remove_edge(0, 1)
+    print("\nAfter removing edge 1-3, the graph is")
+    graph.print()
+
+    # Add vertex
+    graph.add_vertex(6)
+    print("\nAfter adding vertex 6, the graph is")
+    graph.print()
+
+    # Remove vertex
+    # Index of vertex 3 is 1
+    graph.remove_vertex(1)
+    print("\nAfter removing vertex 3, the graph is")
+    graph.print()

en/codes/python/chapter_graph/graph_bfs.py

@@ -0,0 +1,64 @@
+"""
+File: graph_bfs.py
+Created Time: 2023-02-23
+Author: krahets (krahets@163.com)
+"""
+
+import sys
+from pathlib import Path
+
+sys.path.append(str(Path(__file__).parent.parent))
+from modules import Vertex, vals_to_vets, vets_to_vals
+from collections import deque
+from graph_adjacency_list import GraphAdjList
+
+
+def graph_bfs(graph: GraphAdjList, start_vet: Vertex) -> list[Vertex]:
+    """Breadth-first traversal"""
+    # Use adjacency list to represent the graph, to obtain all adjacent vertices of a specified vertex
+    # Vertex traversal sequence
+    res = []
+    # Hash set, used to record visited vertices
+    visited = set[Vertex]([start_vet])
+    # Queue used to implement BFS
+    que = deque[Vertex]([start_vet])
+    # Starting from vertex vet, loop until all vertices are visited
+    while len(que) > 0:
+        vet = que.popleft()  # Dequeue the vertex at the head of the queue
+        res.append(vet)  # Record visited vertex
+        # Traverse all adjacent vertices of that vertex
+        for adj_vet in graph.adj_list[vet]:
+            if adj_vet in visited:
+                continue  # Skip already visited vertices
+            que.append(adj_vet)  # Only enqueue unvisited vertices
+            visited.add(adj_vet)  # Mark the vertex as visited
+    # Return the vertex traversal sequence
+    return res
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    # Initialize undirected graph
+    v = vals_to_vets([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
+    edges = [
+        [v[0], v[1]],
+        [v[0], v[3]],
+        [v[1], v[2]],
+        [v[1], v[4]],
+        [v[2], v[5]],
+        [v[3], v[4]],
+        [v[3], v[6]],
+        [v[4], v[5]],
+        [v[4], v[7]],
+        [v[5], v[8]],
+        [v[6], v[7]],
+        [v[7], v[8]],
+    ]
+    graph = GraphAdjList(edges)
+    print("\nAfter initialization, the graph is")
+    graph.print()
+
+    # Breadth-first traversal
+    res = graph_bfs(graph, v[0])
+    print("\nBreadth-first traversal (BFS) vertex sequence is")
+    print(vets_to_vals(res))

en/codes/python/chapter_graph/graph_dfs.py

@@ -0,0 +1,57 @@
+"""
+File: graph_dfs.py
+Created Time: 2023-02-23
+Author: krahets (krahets@163.com)
+"""
+
+import sys
+from pathlib import Path
+
+sys.path.append(str(Path(__file__).parent.parent))
+from modules import Vertex, vets_to_vals, vals_to_vets
+from graph_adjacency_list import GraphAdjList
+
+
+def dfs(graph: GraphAdjList, visited: set[Vertex], res: list[Vertex], vet: Vertex):
+    """Depth-first traversal helper function"""
+    res.append(vet)  # Record visited vertex
+    visited.add(vet)  # Mark the vertex as visited
+    # Traverse all adjacent vertices of that vertex
+    for adjVet in graph.adj_list[vet]:
+        if adjVet in visited:
+            continue  # Skip already visited vertices
+        # Recursively visit adjacent vertices
+        dfs(graph, visited, res, adjVet)
+
+
+def graph_dfs(graph: GraphAdjList, start_vet: Vertex) -> list[Vertex]:
+    """Depth-first traversal"""
+    # Use adjacency list to represent the graph, to obtain all adjacent vertices of a specified vertex
+    # Vertex traversal sequence
+    res = []
+    # Hash set, used to record visited vertices
+    visited = set[Vertex]()
+    dfs(graph, visited, res, start_vet)
+    return res
+
+
+"""Driver Code"""
+if __name__ == "__main__":
+    # Initialize undirected graph
+    v = vals_to_vets([0, 1, 2, 3, 4, 5, 6])
+    edges = [
+        [v[0], v[1]],
+        [v[0], v[3]],
+        [v[1], v[2]],
+        [v[2], v[5]],
+        [v[4], v[5]],
+        [v[5], v[6]],
+    ]
+    graph = GraphAdjList(edges)
+    print("\nAfter initialization, the graph is")
+    graph.print()
+
+    # Depth-first traversal
+    res = graph_dfs(graph, v[0])
+    print("\nDepth-first traversal (DFS) vertex sequence is")
+    print(vets_to_vals(res))