数据结构二叉树

  1 #include <bits/stdc++.h>
  2 #define null NULL
  3 #define maxn 500005
  4 
  5 typedef long long ll;
  6 
  7 using namespace std;
  8 
  9 typedef struct tree//二叉树的定义
 10 {
 11     char data;
 12     tree *left;
 13     tree *right;
 14 }tree,*netree;
 15 
 16 //创建一个先序二叉树
 17 netree createtree()
 18 {
 19     char c;
 20     cin >> c;
 21     netree root;
 22     if(c == ‘#‘) root = null;
 23     else
 24     {
 25         root = new tree;
 26         root -> data = c;
 27         root -> left = createtree();
 28         root -> right = createtree();
 29     }
 30     return root;
 31 }
 32 
 33 //输出递归先序二叉树
 34 void pretree(netree root)
 35 {
 36     if(root)
 37     {
 38         cout << root -> data << " ";
 39         pretree(root -> left);
 40         pretree(root -> right);
 41     }
 42 }
 43 
 44 //输出递归中序二叉树
 45 void midtree(netree root)
 46 {
 47     if(root)
 48     {
 49         midtree(root -> left);
 50         cout << root -> data << " ";
 51         midtree(root -> right);
 52     }
 53 }
 54 
 55 //输出递归后序二叉树
 56 void endtree(netree root)
 57 {
 58     if(root)
 59     {
 60         endtree(root -> left);
 61         endtree(root -> right);
 62         cout << root -> data << " ";
 63     }
 64 }
 65 
 66 //层次遍历
 67 void every(netree root)
 68 {
 69     queue<netree> q;
 70     if(root)
 71     {
 72         q.push(root);
 73         while(!q.empty())
 74         {
 75             netree p;
 76             p = q.front();
 77             q.pop();
 78             cout << p -> data << " ";
 79             if(p -> left)q.push(p -> left);
 80             if(p -> right)q.push(p -> right);
 81         }
 82     }
 83 }
 84 
 85 void mid_tree(netree root)
 86 {
 87     stack<netree>s;
 88     while(!s.empty() || root)
 89     {
 90         if(root)
 91         {
 92             s.push(root);
 93             root = root -> left;
 94         }
 95         else
 96         {
 97             netree p;
 98             p = s.top();
 99             s.pop();
100             cout << p -> data << " ";
101             root = p -> right;
102         }
103     }
104 
105 }
106 
107 int main()
108 {
109     netree root;
110 
111     cout << "请输入一个先序的二叉树（以#为空）来建立二叉树" << endl;
112     root = createtree();
113 
114     cout << "二叉树的递归先序遍历是" <<endl;
115     pretree(root);
116     cout << endl;
117 
118     cout << "二叉树的递归中序遍历是" <<endl;
119     midtree(root);
120     cout << endl;
121 
122     cout << "二叉树的递归后序遍历是" <<endl;
123     endtree(root);
124     cout << endl;
125 
126     cout << "二叉树的层次遍历是" <<endl;
127     every(root);
128     cout << endl;
129 
130     cout << "二叉树的非递归中序遍历是" <<endl;
131     mid_tree(root);
132     cout << endl;
133 }
134 
135 /*
136 A##
137 ABC####
138 AB##C##
139 ABCD###EF##G##H##
140 A##B##
141 */