(C语言)二叉树非递归后序(数据结构十五)
1.数据类型定义
在代码中为了清楚的表示一些错误和函数运行状态,我们预先定义一些变量来表示这些状态。在head.h头文件中有如下定义:
//定义数据结构中要用到的一些变量和类型 #ifndef HEAD_H #define HEAD_H #include <stdio.h> #include <malloc.h> #include <stdlib.h> #include <math.h> #define TRUE 1 #define FALSE 0 #define OK 1 #define ERROR 0 #define INFEASIBLE -1 #define OVERFLOW -2 //分配内存出错 typedef int Status; //函数返回值类型 typedef int ElemType; //用户定义的数据类型 #endif2.非递归过程中需要用到栈
LinkStack.h代码如下:
#ifndef LINKSTACK_H #define LINKSTACK_H #include "head.h" //可用栈类型Stack的相关定义: typedef struct SElemType { pBiNode root; //二叉树结点的指针类型 int tag; // 0..1 }SElemType,*pType; //栈的元素类型 typedef SElemType Type; typedef struct Node{ Type data; struct Node* next; }Node,*pNode; typedef struct Stack{ pNode base; pNode top; int length; }Stack,*pStack; //初始化栈 Status InitStack(pStack &S){ S=(pStack)malloc(sizeof(Stack)); if(!S) return OVERFLOW; S->length=0; S->base=(pNode)malloc(sizeof(Node)); if(!S->base) return OVERFLOW; S->top=(pNode)malloc(sizeof(Node)); if(!S->top) return OVERFLOW; S->top->next=S->base; return OK; } Status freeStack(pStack &S){ free(S); S=NULL; return OK; } //清空栈 Status ClearStack(pStack &S){ if(S==NULL) return ERROR; pNode p=S->top; while(p->next!=S->base){ pNode q=p; p=p->next; free(q); q=NULL; } S->top=p; S->length=0; return OK; } //销毁栈 Status DestroyStack(pStack S){ if(S==NULL) return ERROR; ClearStack(S); free(S->base); S->base=NULL; free(S->top); S->top=NULL; freeStack(S); S==NULL; return OK; } //栈是否为空 Status StackEmpty(pStack S){ return S->length<=0; } //栈长度 int StackLength(pStack S){ return S->length; } //得到栈顶数据级e Status GetTop(pStack S,Type *e){ *e=S->top->next->data; return OK; } //入栈 Status Push(pStack &S,Type* e){ if(S->length==0){ S->base->data=*e; } else{ pNode p=S->top; p->data=*e; pNode q=(pNode)malloc(sizeof(Node)); q->next=p; S->top=q; } S->length++; return OK; } //出栈 Status Pop(pStack S,Type *e){ if (S->length<=0) return ERROR; if(S->length==1){ *e=S->base->data; S->length--; }else{ pNode p=S->top; S->top=p->next; *e=S->top->data; free(p); S->length--; } return OK; } Status print(Type e){ printf("%d\n",e); return OK; } //用vistit遍历栈 Status StackTraverse(pStack S,Status(*visit)(Type)){ pNode p=S->top; do { p=p->next; (*visit)(p->data); } while (p!=S->base); return OK; } Status printStack(pStack S){ if (S==NULL ||S->length==0) return ERROR; StackTraverse(S,print); return OK; } #endif
3.二叉树头文件
BiTree.h代码如下:
#ifndef BITREE_H #define BITREE_H #include "head.h" typedef struct BiNode{ ElemType data; struct BiNode *left,*right; }BiNode,*pBiNode; Status InsertRight(pBiNode &root,ElemType e); Status InsertLeft(pBiNode &root,ElemType e); Status InitBiTree(pBiNode &tree){ tree=(pBiNode)malloc(sizeof(BiNode)); if(!tree) return OVERFLOW; tree->data=-999999; tree->left=NULL; tree->right=NULL; return OK; } Status BiTreeEmpty(pBiNode root){ if(root==NULL) return ERROR; return root->left==root->right && root->data==-999999; } Status HasNoNode(pBiNode root){ if(root==NULL) return ERROR; return root->left==root->right ; } Status CreatTreeNode(pBiNode &node,ElemType e){ node=(pBiNode)malloc(sizeof(BiNode)); if(!node) return OVERFLOW; node->data=e; node->left=NULL; node->right=NULL; return OK; } Status InsertRight(pBiNode &root,ElemType e){ if(root->right==NULL){ if(e>root->data){ pBiNode p; CreatTreeNode(p,e); root->right=p; return OK; }else{ pBiNode p; CreatTreeNode(p,e); root->left=p; return OK; } }else{ e>root->data? InsertRight(root->right,e):InsertLeft(root,e); } } Status InsertLeft(pBiNode &root,ElemType e){ if(root->left==NULL){ if(e>root->data){ pBiNode p; CreatTreeNode(p,e); root->right=p; return OK; }else{ pBiNode p; CreatTreeNode(p,e); root->left=p; return OK; } }else{ e<=root->data?InsertLeft(root->left,e):InsertRight(root,e); } } Status InsertTree(pBiNode &root,ElemType e){ if(BiTreeEmpty(root)){ root->data=e; return true; } if(e>root->data){ InsertRight(root,e); }else{ InsertLeft(root,e); } } Status CreateBiTree(pBiNode &root,ElemType *a,int n){ for (int i=0;i<n;i++) { InsertTree(root,a[i]); } return true; } Status print(ElemType e ){ printf("%d ",e); return true; } Status PreOrderTraverse(pBiNode root,Status(*p)(int)){ if(root){ (*p)(root->data); PreOrderTraverse(root->left,p); PreOrderTraverse(root->right,p); } return OK; } Status MiddleOrderTraverse(pBiNode root,Status(*p)(int)){ if(root){ MiddleOrderTraverse(root->left,p); (*p)(root->data); MiddleOrderTraverse(root->right,p); } return OK; } Status AfterOrderTraverse(pBiNode root,Status(*p)(int)){ if(root){ AfterOrderTraverse(root->left,p); AfterOrderTraverse(root->right,p); (*p)(root->data); } return OK; } Status ClearBiTree(pBiNode &root){ if(root){ ClearBiTree(root->left); ClearBiTree(root->right); free(root); root==NULL; } return OK; } #endif
4.测试代码
#include "BiTree.h" #include "LinkStack.h" //非北递归后序 void PostOrder(pBiNode root){ pStack s; InitStack(s); pType p,t; p=(pType)malloc(sizeof(SElemType)); t=(pType)malloc(sizeof(SElemType)); p->root=root; while(p->root ||!StackEmpty(s)) { while(p->root) { p->tag= 0; Push(s,p); //printf("%d ",p->root->data); p->root=p->root->left; } GetTop(s,t); while(t->tag && !StackEmpty(s)) { Pop(s,p); printf("%d ",p->root->data); GetTop(s,t); } if(!StackEmpty(s)){ GetTop(s,t); t->tag=1; Pop(s,p); Push(s,t); GetTop(s,p); p->root=p->root->right; }else{ break; } } } void main(){ ElemType a[14]={100,50,200,40,30,45,60,55,61,200,150,300,250,400}; pBiNode root; InitBiTree(root); CreateBiTree(root,a,14); printf("前序:"); PreOrderTraverse(root,print); printf("\n中序:"); MiddleOrderTraverse(root,print); printf("\n后序:"); AfterOrderTraverse(root,print); printf("\n非递归后序:"); PostOrder(root); printf("\n"); ClearBiTree(root); }插入的二叉树为:
5.运行结果: