2013-01-21
摘要：普通树的深度（先根、后根）遍历，和广度遍历。
1. 定义树（这里树节点多出一个visited状态变量）
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1 using System; 2 using System.Collections.Generic; 3 4 namespace TreeTraverse 5 { 6 public class TreeNode<T> 7 { 8 //节点数据 9 private T _data; 10 //左子节点 11 private List<TreeNode<T>> _children; 12 13 private bool _visited; 14 15 public bool Visited 16 { 17 get { return _visited; } 18 set { _visited = value; } 19 } 20 21 public List<TreeNode<T>> Children 22 { 23 get { return _children; } 24 set { _children = value; } 25 } 26 27 public T Data 28 { 29 get { return _data; } 30 set { _data = value; } 31 } 32 33 public TreeNode() 34 { 35 _children = new List<TreeNode<T>>(); 36 _visited = false; 37 } 38 39 public TreeNode(T data) 40 : this() 41 { 42 _data = data; 43 } 44 45 } 46 47 class Tree<T> 48 { 49 private TreeNode<T> _head; 50 51 public TreeNode<T> Head 52 { 53 get { return _head; } 54 set { _head = value; } 55 } 56 57 public static TreeNode<T> GetUnVisitedChild(TreeNode<T> tNode) 58 { 59 foreach (TreeNode<T> node in tNode.Children) 60 { 61 if (node.Visited == false) 62 return node; 63 } 64 return null; 65 } 66 67 public void AddLinkToChild(TreeNode<T> tNode, TreeNode<T> tChild) 68 { 69 tNode.Children.Add(tChild); 70 } 71 } 72 }
2. 遍历树
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1 using System; 2 using System.Collections.Generic; 3 4 namespace TreeTraverse 5 { 6 class Program 7 { 8 static void Main(string[] args) 9 { 10 //先初始化二叉树（要遍历它，当然要先对它进行初始化了~~） 11 //先初始化A/B/C/D/E/F/G/H这些节点 12 TreeNode<string> nodeA = new TreeNode<string>("A"); 13 TreeNode<string> nodeB = new TreeNode<string>("B"); 14 TreeNode<string> nodeC = new TreeNode<string>("C"); 15 TreeNode<string> nodeD = new TreeNode<string>("D"); 16 TreeNode<string> nodeE = new TreeNode<string>("E"); 17 TreeNode<string> nodeF = new TreeNode<string>("F"); 18 TreeNode<string> nodeG = new TreeNode<string>("G"); 19 TreeNode<string> nodeH = new TreeNode<string>("H"); 20 TreeNode<string> nodeI = new TreeNode<string>("I"); 21 22 //再将这些节点建立关系，让其形成一棵名符其实的二叉树 23 Tree<string> tree=new Tree<string>(); 24 tree.Head = nodeA; 25 tree.AddLinkToChild(nodeA, nodeB); 26 tree.AddLinkToChild(nodeA, nodeI); 27 tree.AddLinkToChild(nodeA, nodeC); 28 tree.AddLinkToChild(nodeB, nodeD); 29 tree.AddLinkToChild(nodeC, nodeE); 30 tree.AddLinkToChild(nodeC, nodeF); 31 tree.AddLinkToChild(nodeD, nodeG); 32 tree.AddLinkToChild(nodeD, nodeH); 33 34 /// A 35 /// / | \ 36 /// B I C 37 /// \ / \ 38 /// D E F 39 /// / \ 40 /// G H 41 42 while (true) 43 { 44 Console.WriteLine(); 45 Console.WriteLine("1、先根深度优先"); 46 Console.WriteLine("2、后根深度优先"); 47 Console.WriteLine("3、广度优先"); 48 Console.Write("input num："); 49 50 string num = Console.ReadLine(); 51 switch (num) 52 { 53 case "1": 54 { 55 Console.WriteLine("Correct Sequence should be: \r\nA B D G H I C E F"); 56 Console.WriteLine("先根深度递归优先"); 57 ClearStatus<string>(tree.Head); 58 RootFirst<string>(tree.Head); 59 Console.WriteLine("\r\n先根深度非递归优先"); 60 ClearStatus<string>(tree.Head); 61 RootFirstNonRec<string>(tree.Head); 62 break; 63 } 64 65 case "2": 66 { 67 Console.WriteLine("Correct Sequence should be: \r\nG H D B I E F C A"); 68 Console.WriteLine("后根深度非递归优先"); 69 ClearStatus<string>(tree.Head); 70 RootLast<string>(tree.Head); 71 Console.WriteLine("\r\n后根深度非递归优先"); 72 ClearStatus<string>(tree.Head); 73 RootLastNonRec<string>(tree.Head); 74 break; 75 } 76 case "3": 77 { 78 Console.WriteLine("广度优先"); 79 BFSTraverse<string>(tree.Head); 80 break; 81 } 82 default: break; 83 } 84 } 85 } 86 87 //先根深度优先 88 protected static void RootFirst<T>(TreeNode<T> root) 89 { 90 if (root != null) 91 { 92 Console.Write(root.Data + " "); 93 foreach (TreeNode<T> node in root.Children) 94 RootFirst(node); 95 } 96 } 97 98 //先根深度优先非递归 99 protected static void RootFirstNonRec<T>(TreeNode<T> root) 100 { 101 TreeNode<T> p = root; 102 Stack<TreeNode<T>> s = new Stack<TreeNode<T>>(); 103 while (p != null || s.Count != 0) 104 { 105 while (p != null) 106 { 107 Console.Write(p.Data + " "); 108 p.Visited = true; 109 s.Push(p); 110 p = Tree<T>.GetUnVisitedChild(p); 111 } 112 s.Pop(); 113 if (s.Count != 0) 114 { 115 p = s.Peek(); 116 p = Tree<T>.GetUnVisitedChild(p); 117 } 118 } 119 } 120 121 //后根深度优先 122 protected static void RootLast<T>(TreeNode<T> root) 123 { 124 if (root != null) 125 { 126 foreach (TreeNode<T> node in root.Children) 127 RootLast(node); 128 Console.Write(root.Data + " "); 129 } 130 } 131 132 //后根深度优先非递归 133 protected static void RootLastNonRec<T>(TreeNode<T> root) 134 { 135 TreeNode<T> p = root; 136 Stack<TreeNode<T>> s = new Stack<TreeNode<T>>(); 137 while (p != null || s.Count != 0) 138 { 139 while (p != null) 140 { 141 p.Visited = true; 142 s.Push(p); 143 p = Tree<T>.GetUnVisitedChild(p); 144 } 145 Console.Write(s.Pop().Data+ " "); 146 if (s.Count != 0) 147 { 148 p = s.Peek(); 149 p = Tree<T>.GetUnVisitedChild(p); 150 } 151 } 152 } 153 154 //Breadth-First Traverse 广度优先 155 protected static void BFSTraverse<T>(TreeNode<T> root) 156 { 157 TreeNode<T> p = root; 158 Queue<TreeNode<T>> q = new Queue<TreeNode<T>>(); 159 q.Enqueue(p); 160 while (q.Count != 0) 161 { 162 p = q.Dequeue(); 163 Console.Write(p.Data + " "); 164 foreach (TreeNode<T> tNode in p.Children) 165 { 166 q.Enqueue(tNode); 167 } 168 } 169 } 170 171 //清除状态 172 protected static void ClearStatus<T>(TreeNode<T> root) 173 { 174 TreeNode<T> p = root; 175 Queue<TreeNode<T>> q = new Queue<TreeNode<T>>(); 176 q.Enqueue(p); 177 while (q.Count != 0) 178 { 179 p = q.Dequeue(); 180 p.Visited = false; 181 foreach (TreeNode<T> tNode in p.Children) 182 { 183 q.Enqueue(tNode); 184 } 185 } 186 } 187 } 188 }