Rename the common modules.

.gitignore

@@ -12,7 +12,7 @@ docs/overrides/
 # build
 build/
 site/
-utils/
+./utils/
 
 # test script
 test.sh

codes/csharp/chapter_array_and_linkedlist/linked_list.cs

@@ -2,7 +2,7 @@
 // Created Time: 2022-12-16
 // Author: mingXta ([email protected])
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_array_and_linkedlist;

codes/csharp/chapter_backtracking/preorder_traversal_i_compact.cs

@@ -4,7 +4,7 @@
  * Author: hpstory ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 using System.IO;
 

codes/csharp/chapter_backtracking/preorder_traversal_ii_compact.cs

@@ -4,7 +4,7 @@
  * Author: hpstory ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_backtracking;

codes/csharp/chapter_backtracking/preorder_traversal_iii_compact.cs

@@ -4,7 +4,7 @@
  * Author: hpstory ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_backtracking;

codes/csharp/chapter_backtracking/preorder_traversal_iii_template.cs

@@ -4,7 +4,7 @@
  * Author: hpstory ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_backtracking;

codes/csharp/chapter_computational_complexity/space_complexity.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_computational_complexity;

codes/csharp/chapter_graph/graph_adjacency_list.cs

@@ -4,7 +4,7 @@
  * Author: zjkung1123 ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_graph;

codes/csharp/chapter_graph/graph_adjacency_matrix.cs

@@ -4,7 +4,7 @@
  * Author: zjkung1123 ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_graph;

codes/csharp/chapter_graph/graph_bfs.cs

@@ -4,7 +4,7 @@
  * Author: hpstory ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_graph;

codes/csharp/chapter_graph/graph_dfs.cs

@@ -4,7 +4,7 @@
  * Author: hpstory ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_graph;

codes/csharp/chapter_hashing/hash_map.cs

@@ -5,7 +5,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_hashing;

codes/csharp/chapter_heap/heap.cs

@@ -4,7 +4,7 @@
  * Author: zjkung1123 ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_heap;

codes/csharp/chapter_heap/my_heap.cs

@@ -4,7 +4,7 @@
  * Author: zjkung1123 ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_heap;

codes/csharp/chapter_searching/hashing_search.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_searching;

codes/csharp/chapter_searching/linear_search.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_searching;

codes/csharp/chapter_stack_and_queue/linkedlist_queue.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_stack_and_queue;

codes/csharp/chapter_stack_and_queue/linkedlist_stack.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_stack_and_queue;

codes/csharp/chapter_tree/avl_tree.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_tree;

codes/csharp/chapter_tree/binary_search_tree.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_tree;

codes/csharp/chapter_tree/binary_tree.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_tree;

codes/csharp/chapter_tree/binary_tree_bfs.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_tree;

codes/csharp/chapter_tree/binary_tree_dfs.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-using hello_algo.include;
+using hello_algo.utils;
 using NUnit.Framework;
 
 namespace hello_algo.chapter_tree;

codes/csharp/include/ListNode.cs → codes/csharp/utils/ListNode.cs

@@ -2,7 +2,7 @@
 // Created Time: 2022-12-16
 // Author: mingXta ([email protected])
 
-namespace hello_algo.include;
+namespace hello_algo.utils;
 
 /* Definition for a singly-linked list node */
 public class ListNode {

codes/csharp/include/PrintUtil.cs → codes/csharp/utils/PrintUtil.cs

@@ -4,7 +4,7 @@
 * Author: haptear ([email protected]), krahets ([email protected])
 */
 
-namespace hello_algo.include;
+namespace hello_algo.utils;
 
 public class Trunk {
     public Trunk? prev;

codes/csharp/include/TreeNode.cs → codes/csharp/utils/TreeNode.cs

@@ -4,7 +4,7 @@
  * Author: haptear ([email protected])
  */
 
-namespace hello_algo.include;
+namespace hello_algo.utils;
 
 /* 二叉树节点类 */
 public class TreeNode {

codes/csharp/include/Vertex.cs → codes/csharp/utils/Vertex.cs

@@ -4,7 +4,7 @@
  * Author: zjkung1123 ([email protected]), krahets ([email protected])
  */
 
-namespace hello_algo.include;
+namespace hello_algo.utils;
 
 /* 顶点类 */
 public class Vertex {

codes/java/utils/ListNode.java

@@ -0,0 +1,36 @@
+/**
+ * File: ListNode.java
+ * Created Time: 2022-11-25
+ * Author: Krahets ([email protected])
+ */
+
+package utils;
+
+/* Definition for a singly-linked list node */
+public class ListNode {
+    public int val;
+    public ListNode next;
+
+    public ListNode(int x) {
+        val = x;
+    }
+
+    /* Generate a linked list with an array */
+    public static ListNode arrToLinkedList(int[] arr) {
+        ListNode dum = new ListNode(0);
+        ListNode head = dum;
+        for (int val : arr) {
+            head.next = new ListNode(val);
+            head = head.next;
+        }
+        return dum.next;
+    }
+
+    /* Get a list node with specific value from a linked list */
+    public static ListNode getListNode(ListNode head, int val) {
+        while (head != null && head.val != val) {
+            head = head.next;
+        }
+        return head;
+    }
+}

codes/java/utils/PrintUtil.java

@@ -0,0 +1,118 @@
+/**
+ * File: PrintUtil.java
+ * Created Time: 2022-11-25
+ * Author: Krahets ([email protected])
+ */
+
+package utils;
+
+import java.util.*;
+
+class Trunk {
+    Trunk prev;
+    String str;
+
+    Trunk(Trunk prev, String str) {
+        this.prev = prev;
+        this.str = str;
+    }
+};
+
+public class PrintUtil {
+
+    /* Print a matrix (Array) */
+    public static <T> void printMatrix(T[][] matrix) {
+        System.out.println("[");
+        for (T[] row : matrix) {
+            System.out.println("  " + row + ",");
+        }
+        System.out.println("]");
+    }
+
+    /* Print a matrix (List) */
+    public static <T> void printMatrix(List<List<T>> matrix) {
+        System.out.println("[");
+        for (List<T> row : matrix) {
+            System.out.println("  " + row + ",");
+        }
+        System.out.println("]");
+    }
+
+    /* Print a linked list */
+    public static void printLinkedList(ListNode head) {
+        List<String> list = new ArrayList<>();
+        while (head != null) {
+            list.add(String.valueOf(head.val));
+            head = head.next;
+        }
+        System.out.println(String.join(" -> ", list));
+    }
+
+    /**
+     * The interface of the tree printer
+     * This tree printer is borrowed from TECHIE DELIGHT
+     * https://www.techiedelight.com/c-program-print-binary-tree/
+     */
+    public static void printTree(TreeNode root) {
+        printTree(root, null, false);
+    }
+
+    /* Print a binary tree */
+    public static void printTree(TreeNode root, Trunk prev, boolean isLeft) {
+        if (root == null) {
+            return;
+        }
+
+        String prev_str = "    ";
+        Trunk trunk = new Trunk(prev, prev_str);
+
+        printTree(root.right, trunk, true);
+
+        if (prev == null) {
+            trunk.str = "———";
+        } else if (isLeft) {
+            trunk.str = "/———";
+            prev_str = "   |";
+        } else {
+            trunk.str = "\\———";
+            prev.str = prev_str;
+        }
+
+        showTrunks(trunk);
+        System.out.println(" " + root.val);
+
+        if (prev != null) {
+            prev.str = prev_str;
+        }
+        trunk.str = "   |";
+
+        printTree(root.left, trunk, false);
+    }
+
+    /* Helper function to print branches of the binary tree */
+    public static void showTrunks(Trunk p) {
+        if (p == null) {
+            return;
+        }
+
+        showTrunks(p.prev);
+        System.out.print(p.str);
+    }
+
+    /* Print a hash map */
+    public static <K, V> void printHashMap(Map<K, V> map) {
+        for (Map.Entry<K, V> kv : map.entrySet()) {
+            System.out.println(kv.getKey() + " -> " + kv.getValue());
+        }
+    }
+
+    /* Print a heap (PriorityQueue) */
+    public static void printHeap(Queue<Integer> queue) {
+        List<Integer> list = new ArrayList<>(queue);
+        System.out.print("堆的数组表示：");
+        System.out.println(list);
+        System.out.println("堆的树状表示：");
+        TreeNode root = TreeNode.listToTree(list);
+        printTree(root);
+    }
+}