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
2026-02-13 23:55:39 +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_bfs.java
+++ b/en/codes/java/chapter_graph/graph_bfs.java
@@ -0,0 +1,55 @@
+/**
+ * File: graph_bfs.java
+ * Created Time: 2023-02-12
+ * Author: krahets (krahets@163.com)
+ */
+
+package chapter_graph;
+
+import java.util.*;
+import utils.*;
+
+public class graph_bfs {
+    /* Breadth-first traversal */
+    // Use adjacency list to represent the graph, to obtain all adjacent vertices of a specified vertex
+    static List<Vertex> graphBFS(GraphAdjList graph, Vertex startVet) {
+        // Vertex traversal sequence
+        List<Vertex> res = new ArrayList<>();
+        // Hash set, used to record visited vertices
+        Set<Vertex> visited = new HashSet<>();
+        visited.add(startVet);
+        // Queue used to implement BFS
+        Queue<Vertex> que = new LinkedList<>();
+        que.offer(startVet);
+        // Starting from vertex vet, loop until all vertices are visited
+        while (!que.isEmpty()) {
+            Vertex vet = que.poll(); // Dequeue the vertex at the head of the queue
+            res.add(vet);            // Record visited vertex
+            // Traverse all adjacent vertices of that vertex
+            for (Vertex adjVet : graph.adjList.get(vet)) {
+                if (visited.contains(adjVet))
+                    continue;        // Skip already visited vertices
+                que.offer(adjVet);   // Only enqueue unvisited vertices
+                visited.add(adjVet); // Mark the vertex as visited
+            }
+        }
+        // Return the vertex traversal sequence
+        return res;
+    }
+
+    public static void main(String[] args) {
+        /* Initialize undirected graph */
+        Vertex[] v = Vertex.valsToVets(new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 });
+        Vertex[][] 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] } };
+        GraphAdjList graph = new GraphAdjList(edges);
+        System.out.println("\nAfter initialization, the graph is");
+        graph.print();
+
+        /* Breadth-first traversal */
+        List<Vertex> res = graphBFS(graph, v[0]);
+        System.out.println("\nBreadth-first traversal (BFS) vertex sequence is");
+        System.out.println(Vertex.vetsToVals(res));
+    }
+}