二叉樹的非遞歸算法總結

    二叉樹的非遞歸算法，採用棧實現，本文給出了從設置棧到利用棧的完整代碼，其中二叉樹的後序遍歷需要採用標誌位，這樣纔可以有序的變非線性的結構爲線性結構，二叉樹生成的過程沒有考慮平衡性的影響。期待下一步實現平衡二叉樹遍歷的實例。

 

 

#include <stdlib.h> #include <stdio.h> #include <conio.h> #define maxsize 30 typedef struct BinaryTree { int key; struct BinaryTree *left; struct BinaryTree *right; }Node,*node; typedef struct { Node* data[maxsize]; int top; }SeqStack; SeqStack* StackInitialize() { SeqStack *s; s=(SeqStack* )malloc(sizeof(SeqStack)); if(s==NULL) { printf("Stack Overflow/n"); return NULL; } else { s->top=-1; return s; } } int IsEmpty(SeqStack* s) { if(s->top==-1) return 1; else return 0; } int Push(SeqStack* s,Node* data) { if(s->top==maxsize-1) { printf("The stack is full!/n"); return 0; } else { s->top++; s->data[s->top]=data; return 1; } } Node* Pop(SeqStack* s) { Node* data; if(IsEmpty(s)) { printf("The stack is empty!/n"); return NULL; } else { data=s->data[s->top]; s->top--; return data; } } Node* gettop(SeqStack* s) { Node* data; data=s->data[s->top]; return data; } Node *InsertNode(Node* root,int val) { Node* temp; if (root==NULL) { temp=(Node* )malloc(sizeof(Node)); root=temp; root->key=val; root->left=NULL; root->right=NULL; } else { if(val<=root->key) root->left=InsertNode(root->left,val); else root->right=InsertNode(root->right,val); } return(root); } void deleteTree(Node *root) { if (root->left!=NULL) deleteTree(root->left); if(root->right!=NULL) deleteTree(root->right); deleteTree(root); return; } void PreOrder(Node *root) { SeqStack* s; Node* p; p=root; s=StackInitialize(); if(root=NULL) printf("The tree is empty!/n"); while(p!=NULL||!IsEmpty(s)) { if (p!=NULL) { Push(s,p); printf("%d ",p->key); p=p->left; } else { p=Pop(s); p=p->right; } } } void InOrder(Node* root) { SeqStack *s; Node *p; p=root; s=StackInitialize(); if (root==NULL) printf("The Tree is empty/n"); while(p!=NULL||!IsEmpty(s)) { if (p!=NULL) { Push(s,p); p=p->left; } else { p=Pop(s); printf("%d ",p->key); p=p->right; } } } void PostOrder(Node* root) { SeqStack *s; Node *p,*q; p=root; int flag[maxsize]; s=StackInitialize(); if (root==NULL) printf("The Tree is empty/n"); while(p!=NULL||!IsEmpty(s)) { while (p!=NULL) { Push(s,p); flag[s->top]=0; p=p->left; } while(!IsEmpty(s)&&flag[s->top]==1) { p=Pop(s); printf("%d ",p->key); } if (!IsEmpty(s)) { flag[s->top]=1; p=gettop(s); p=p->right; } else break; } } int main() { int val; Node *tree,*root; root=NULL; tree=NULL; while(1) { scanf("%d",&val); if(val<=0) break; else root=InsertNode(root,val); } InOrder(root); printf("/n"); PreOrder(root); printf("/n"); PostOrder(root); deleteTree(root); return 0; } 

 

2010-11-19