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
2026-04-03 18:50:58 +08:00 · 2024-05-06 05:21:51 +08:00
parent b5e198db7d
commit 1c0f350ad6
174 changed files with 12349 additions and 0 deletions
--- a/en/codes/java/chapter_graph/graph_adjacency_matrix.java
+++ b/en/codes/java/chapter_graph/graph_adjacency_matrix.java
@@ -0,0 +1,131 @@
+/**
+ * File: graph_adjacency_matrix.java
+ * Created Time: 2023-01-26
+ * Author: krahets (krahets@163.com)
+ */
+
+package chapter_graph;
+
+import utils.*;
+import java.util.*;
+
+/* Undirected graph class based on adjacency matrix */
+class GraphAdjMat {
+    List<Integer> vertices; // Vertex list, elements represent "vertex value", index represents "vertex index"
+    List<List<Integer>> adjMat; // Adjacency matrix, row and column indices correspond to "vertex index"
+
+    /* Constructor */
+    public GraphAdjMat(int[] vertices, int[][] edges) {
+        this.vertices = new ArrayList<>();
+        this.adjMat = new ArrayList<>();
+        // Add vertex
+        for (int val : vertices) {
+            addVertex(val);
+        }
+        // Add edge
+        // Please note, edges elements represent vertex indices, corresponding to vertices elements indices
+        for (int[] e : edges) {
+            addEdge(e[0], e[1]);
+        }
+    }
+
+    /* Get the number of vertices */
+    public int size() {
+        return vertices.size();
+    }
+
+    /* Add vertex */
+    public void addVertex(int val) {
+        int n = size();
+        // Add new vertex value to the vertex list
+        vertices.add(val);
+        // Add a row to the adjacency matrix
+        List<Integer> newRow = new ArrayList<>(n);
+        for (int j = 0; j < n; j++) {
+            newRow.add(0);
+        }
+        adjMat.add(newRow);
+        // Add a column to the adjacency matrix
+        for (List<Integer> row : adjMat) {
+            row.add(0);
+        }
+    }
+
+    /* Remove vertex */
+    public void removeVertex(int index) {
+        if (index >= size())
+            throw new IndexOutOfBoundsException();
+        // Remove vertex at `index` from the vertex list
+        vertices.remove(index);
+        // Remove the row at `index` from the adjacency matrix
+        adjMat.remove(index);
+        // Remove the column at `index` from the adjacency matrix
+        for (List<Integer> row : adjMat) {
+            row.remove(index);
+        }
+    }
+
+    /* Add edge */
+    // Parameters i, j correspond to vertices element indices
+    public void addEdge(int i, int j) {
+        // Handle index out of bounds and equality
+        if (i < 0 || j < 0 || i >= size() || j >= size() || i == j)
+            throw new IndexOutOfBoundsException();
+        // In an undirected graph, the adjacency matrix is symmetric about the main diagonal, i.e., satisfies (i, j) == (j, i)
+        adjMat.get(i).set(j, 1);
+        adjMat.get(j).set(i, 1);
+    }
+
+    /* Remove edge */
+    // Parameters i, j correspond to vertices element indices
+    public void removeEdge(int i, int j) {
+        // Handle index out of bounds and equality
+        if (i < 0 || j < 0 || i >= size() || j >= size() || i == j)
+            throw new IndexOutOfBoundsException();
+        adjMat.get(i).set(j, 0);
+        adjMat.get(j).set(i, 0);
+    }
+
+    /* Print adjacency matrix */
+    public void print() {
+        System.out.print("Vertex list = ");
+        System.out.println(vertices);
+        System.out.println("Adjacency matrix =");
+        PrintUtil.printMatrix(adjMat);
+    }
+}
+
+public class graph_adjacency_matrix {
+    public static void main(String[] args) {
+        /* Initialize undirected graph */
+        // Please note, edges elements represent vertex indices, corresponding to vertices elements indices
+        int[] vertices = { 1, 3, 2, 5, 4 };
+        int[][] edges = { { 0, 1 }, { 0, 3 }, { 1, 2 }, { 2, 3 }, { 2, 4 }, { 3, 4 } };
+        GraphAdjMat graph = new GraphAdjMat(vertices, edges);
+        System.out.println("\nAfter initialization, the graph is");
+        graph.print();
+
+        /* Add edge */
+        // Indices of vertices 1, 2 are 0, 2 respectively
+        graph.addEdge(0, 2);
+        System.out.println("\nAfter adding edge 1-2, the graph is");
+        graph.print();
+
+        /* Remove edge */
+        // Indices of vertices 1, 3 are 0, 1 respectively
+        graph.removeEdge(0, 1);
+        System.out.println("\nAfter removing edge 1-3, the graph is");
+        graph.print();
+
+        /* Add vertex */
+        graph.addVertex(6);
+        System.out.println("\nAfter adding vertex 6, the graph is");
+        graph.print();
+
+        /* Remove vertex */
+        // Index of vertex 3 is 1
+        graph.removeVertex(1);
+        System.out.println("\nAfter removing vertex 3, the graph is");
+        graph.print();
+    }
+}