C#先序遍歷2叉樹（非遞歸）

找了下先序遍歷二叉樹C# 實現貌似沒有 順手些了一個

大致思路是：

傳入根節點，然后依次循環其子節點推入到棧中，

當推入的節點沒有子節點的時候（葉子）或者所有子節點均已經遍歷過后（上一次遍歷的節點是該節點的右子節點），再依次退出棧。

  1 using System;  2 using System.Collections.Generic;  3 using System.Linq;  4 using System.Text;  5 using System.Threading.Tasks;  6    7 namespace Consoleapplication5  8 {  9     class PRogram 10     { 11         static void Main(string[] args) 12         { 13             Node treeRoot = CreateTree(); 14             scanTree(treeRoot); 15         } 16   17         private static void scanTree(Node treeRoot) 18         { 19             List<Node> list = new List<Node>(); 20             list.Add(treeRoot); 21             Node point = treeRoot; 22             Write(treeRoot); 23             while (true) 24             { 25                 if (!list.Contains(point)) 26                 { //上一輪是移除的操作 27                     if (treeRoot.leftSon == point) 28                     {//移除的是左結點 29                         if (treeRoot.rightSon != null) 30                         { 31                             treeRoot = treeRoot.rightSon; 32                             list.Add(treeRoot); 33                             Write(treeRoot); 34                             point = treeRoot; 35                             continue; 36                         } 37                         list.Remove(treeRoot); 38                         if (list.Count == 0) 39                         { 40                             break; 41                         } 42                         point = treeRoot; 43                         treeRoot = list[list.Count - 1]; 44                     } 45                     else 46                     {//移除的是右結點 47                         list.Remove(treeRoot); 48                         if (list.Count == 0) 49                         { 50                             break; 51                         } 52                         point = treeRoot; 53                         treeRoot = list[list.Count - 1]; 54                     } 55                     continue; 56                 } 57   58                 if (treeRoot.leftSon != null) 59                 { 60                     treeRoot = treeRoot.leftSon; 61                     Write(treeRoot); 62                     list.Add(treeRoot); 63                     point = treeRoot; 64                     continue; 65                 } 66                 if (treeRoot.rightSon != null) 67                 { 68                     treeRoot = treeRoot.rightSon; 69                     Write(treeRoot); 70                     point = treeRoot; 71                     list.Add(treeRoot); 72                     continue; 73                 } 74                 //當前的節點是葉子節點   if (treeRoot.leftSon == null && treeRoot.rightSon == null) 75                 //{ 76                     list.Remove(treeRoot); 77                     if (list.Count == 0) 78                     { 79                         break; 80                     } 81                     point = treeRoot; 82                     treeRoot = list[list.Count - 1]; 83                // } 84             } 85   86         } 87   88         public static void Write(Node node) 89         { 90             Console.WriteLine(node.Data); 91         } 92   93         private static Node CreateTree() 94         { 95             Node a = new Node("A"); 96            a.leftSon = new Node("B"); 97             a.rightSon = new Node("C"); 98             99            a.leftSon.leftSon = new Node("D");100            a.leftSon.rightSon = new Node("E");101            102            a.rightSon.leftSon = new Node("F");103            a.rightSon.rightSon = new Node("G");104  105            a.leftSon.leftSon.leftSon = new Node("H");106            a.leftSon.leftSon.rightSon = new Node("I");107             return a;108         }109     }110  111     class Node112     {113         public string Data { get; set; }114         public Node leftSon { get; set; }115         public Node rightSon { get; set; }116  117         public Node(string data)118         {119             Data = data;120         }121     }122 }