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An inorder binary tree traversal can be implemented in a non-recursive way with a stack. For example, suppose that when a 6-node binary tree (with the keys numbered from 1 to 6) is traversed, the stack operations are: push(1); push(2); push(3); pop(); pop(); push(4); pop(); pop(); push(5); push(6); pop(); pop(). Then a unique binary tree (shown in Figure 1) can be generated from this sequence of operations. Your task is to give the postorder traversal sequence of this tree.
题意给出先序遍历顺序的节点 然后让你打印出后序遍历
我的方法比较老实 按照先序遍历的顺序构建一棵树 再用后序遍历输出
陈越老师的办法更巧妙 没建树 因为 push进去的是先序顺序 pop出来的是中序 然后分别递归两个顺序可的后序
我不详细介绍了 大家可以去mooc看看
下面是我的C语言代码
1 #include "stdio.h" 2 #include "string.h" 3 #include "stdlib.h" 4 typedef struct bintre 5 { 6 int data; 7 struct bintre *left; 8 struct bintre *right; 9 }BinTree; 10 int n,flag=1; 11 BinTree *CreatTree(BinTree *head); 12 void Traversal(BinTree *head); 13 int main() 14 { 15 int i=0; 16 int a[30]={-1}; 17 BinTree *head,*t; 18 19 scanf("%d ",&n); 20 head=CreatTree(head); 21 Traversal(head); 22 printf("\n"); 23 } 24 void Traversal(BinTree *head) 25 { 26 if(!head) 27 return; 28 Traversal(head->left); 29 Traversal(head->right); 30 if(flag) 31 { 32 printf("%d",head->data); 33 flag=0; 34 } 35 else 36 printf(" %d",head->data); 37 } 38 BinTree *CreatTree(BinTree *head) 39 { 40 int data; 41 char flag[6]; 42 if(n<=0) 43 return NULL; 44 scanf("%s",flag); 45 scanf("%d",&data); 46 47 if(strcmp(flag,"Pop")==0) 48 { 49 head=NULL; 50 return head; 51 } 52 else 53 n--; 54 head=(BinTree *)malloc(sizeof(BinTree )); 55 head->data=data; 56 head->left=CreatTree(head->left); 57 head->right=CreatTree(head->right); 58 59 return head; 60 61 }
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原文地址：http://www.cnblogs.com/threezj/p/4518072.html
