Rename the common modules.

codes/csharp/utils/ListNode.cs

@@ -0,0 +1,44 @@
+// File: ListNode.cs
+// Created Time: 2022-12-16
+// Author: mingXta (1195669834@qq.com)
+
+namespace hello_algo.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;
+        foreach (int val in 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;
+    }
+
+    public override string? ToString() {
+        List<string> list = new();
+        var head = this;
+        while (head != null) {
+            list.Add(head.val.ToString());
+            head = head.next;
+        }
+        return string.Join("->", list);
+    }
+}

codes/csharp/utils/PrintUtil.cs

@@ -0,0 +1,134 @@
+/**
+* File: PrintUtil.cs
+* Created Time: 2022-12-23
+* Author: haptear (haptear@hotmail.com), krahets (krahets@163.com)
+*/
+
+namespace hello_algo.utils;
+
+public class Trunk {
+    public Trunk? prev;
+    public string str;
+
+    public Trunk(Trunk? prev, string str) {
+        this.prev = prev;
+        this.str = str;
+    }
+};
+
+public class PrintUtil {
+    /* Print a list */
+    public static void PrintList<T>(List<T> list) {
+        Console.WriteLine("[" + string.Join(", ", list) + "]");
+    }
+
+    /* Print a matrix (Array) */
+    public static void PrintMatrix<T>(T[][] matrix) {
+        Console.WriteLine("[");
+        foreach (T[] row in matrix) {
+            Console.WriteLine("  " + string.Join(", ", row) + ",");
+        }
+        Console.WriteLine("]");
+    }
+
+    /* Print a matrix (List) */
+    public static void PrintMatrix<T>(List<List<T>> matrix) {
+        Console.WriteLine("[");
+        foreach (List<T> row in matrix) {
+            Console.WriteLine("  " + string.Join(", ", row) + ",");
+        }
+        Console.WriteLine("]");
+    }
+
+    /* Print a linked list */
+    public static void PrintLinkedList(ListNode head) {
+        List<string> list = new();
+        while (head != null) {
+            list.Add(head.val.ToString());
+            head = head.next;
+        }
+        Console.Write(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, bool 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);
+        Console.WriteLine(" " + 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);
+        Console.Write(p.str);
+    }
+
+    /* Print a hash map */
+    public static void PrintHashMap<K, V>(Dictionary<K, V> map) where K : notnull {
+        foreach (var kv in map.Keys) {
+            Console.WriteLine(kv.ToString() + " -> " + map[kv]?.ToString());
+        }
+    }
+
+    /* Print a heap */
+    public static void PrintHeap(Queue<int> queue) {
+        Console.Write("堆的数组表示：");
+        List<int> list = queue.ToList();
+        Console.WriteLine(string.Join(',', list));
+        Console.WriteLine("堆的树状表示：");
+        TreeNode tree = TreeNode.ListToTree(list.Cast<int?>().ToList());
+        PrintTree(tree);
+    }
+
+    /* Print a PriorityQueue */
+    public static void PrintHeap(PriorityQueue<int, int> queue) {
+        var newQueue = new PriorityQueue<int, int>(queue.UnorderedItems, queue.Comparer);
+        Console.Write("堆的数组表示：");
+        List<int> list = new List<int>();
+        while (newQueue.TryDequeue(out int element, out int priority)) {
+            list.Add(element);
+        }
+        Console.WriteLine("堆的树状表示：");
+        Console.WriteLine(string.Join(',', list.ToList()));
+        TreeNode tree = TreeNode.ListToTree(list.Cast<int?>().ToList());
+        PrintTree(tree);
+    }
+}

codes/csharp/utils/TreeNode.cs

@@ -0,0 +1,73 @@
+/**
+ * File: TreeNode.cs
+ * Created Time: 2022-12-23
+ * Author: haptear (haptear@hotmail.com)
+ */
+
+namespace hello_algo.utils;
+
+/* 二叉树节点类 */
+public class TreeNode {
+    public int val;        // 节点值
+    public int height;     // 节点高度
+    public TreeNode? left;  // 左子节点引用
+    public TreeNode? right; // 右子节点引用
+
+    public TreeNode(int x) {
+        val = x;
+    }
+
+    /* Generate a binary tree given an array */
+    public static TreeNode? ListToTree(List<int?> arr) {
+        if (arr.Count == 0 || arr[0] == null)
+            return null;
+
+        TreeNode root = new TreeNode(arr[0]!.Value);
+        Queue<TreeNode> queue = new Queue<TreeNode>();
+        queue.Enqueue(root);
+        int i = 0;
+        while (queue.Count != 0) {
+            TreeNode node = queue.Dequeue();
+            if (++i >= arr.Count) break;
+            if (arr[i] != null) {
+                node.left = new TreeNode((int)arr[i]);
+                queue.Enqueue(node.left);
+            }
+            if (++i >= arr.Count) break;
+            if (arr[i] != null) {
+                node.right = new TreeNode((int)arr[i]);
+                queue.Enqueue(node.right);
+            }
+        }
+        return root;
+    }
+
+    /* Serialize a binary tree to a list */
+    public static List<int?> TreeToList(TreeNode root) {
+        List<int?> list = new();
+        if (root == null) return list;
+        Queue<TreeNode?> queue = new();
+        while (queue.Count != 0) {
+            TreeNode? node = queue.Dequeue();
+            if (node != null) {
+                list.Add(node.val);
+                queue.Enqueue(node.left);
+                queue.Enqueue(node.right);
+            } else {
+                list.Add(null);
+            }
+        }
+        return list;
+    }
+
+    /* Get a tree node with specific value in a binary tree */
+    public static TreeNode? GetTreeNode(TreeNode? root, int val) {
+        if (root == null)
+            return null;
+        if (root.val == val)
+            return root;
+        TreeNode? left = GetTreeNode(root.left, val);
+        TreeNode? right = GetTreeNode(root.right, val);
+        return left ?? right;
+    }
+}

codes/csharp/utils/Vertex.cs

@@ -0,0 +1,33 @@
+/**
+ * File: Vertex.cs
+ * Created Time: 2023-02-06
+ * Author: zjkung1123 (zjkung1123@gmail.com), krahets (krahets@163.com)
+ */
+
+namespace hello_algo.utils;
+
+/* 顶点类 */
+public class Vertex {
+    public int val;
+    public Vertex(int val) {
+        this.val = val;
+    }
+
+    /* 输入值列表 vals ，返回顶点列表 vets */
+    public static Vertex[] ValsToVets(int[] vals) {
+        Vertex[] vets = new Vertex[vals.Length];
+        for (int i = 0; i < vals.Length; i++) {
+            vets[i] = new Vertex(vals[i]);
+        }
+        return vets;
+    }
+
+    /* 输入顶点列表 vets ，返回值列表 vals */
+    public static List<int> VetsToVals(List<Vertex> vets) {
+        List<int> vals = new List<int>();
+        foreach (Vertex vet in vets) {
+            vals.Add(vet.val);
+        }
+        return vals;
+    }
+}