## 各种基本算法实现小结（三）—— 树与二叉树

（均已测试通过）

===================================================================

```#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
struct _node
{
char data;
struct _node *lchild;
struct _node *rchild;
};
typedef struct _node node, *pnode;
pnode create_tree()
{
pnode pt;
char data;
scanf("%c", &data);
getchar();
if(data==' ')
pt=NULL;
else
{
pt=(pnode)malloc(sizeof(node));
pt->data=data;
pt->lchild=create_tree();
pt->rchild=create_tree();
}
return(pt);
}
void print_pretree(pnode ps)
{
if(ps != NULL)
{
printf("%3c", ps->data);
print_pretree(ps->lchild);
print_pretree(ps->rchild);
}
}
void main()
{
pnode ps;
ps=create_tree();
print_pretree(ps);
printf("/n");
}```

===========================================================

```#include <stdio.h>
#include <malloc.h>
struct _node
{
char data;
struct _node *lchild;
struct _node *rchild;
};
typedef struct _node node, *pnode;
int count_l=0;  /* count leaf */
int count_n=0;  /* count node */
pnode create_tree()
{
pnode pt;
char data;
scanf("%c", &data);
getchar();
if(data==' ')
pt=NULL;
else
{
pt=(pnode)malloc(sizeof(node));
pt->data=data;
pt->lchild=create_tree();
pt->rchild=create_tree();
}
return(pt);
}
void print_pretree(pnode ps)
{
if(ps != NULL)
{
printf("%3c", ps->data);
print_pretree(ps->lchild);
print_pretree(ps->rchild);
}
}
void print_midtree(pnode ps)
{
if(ps != NULL)
{
print_midtree(ps->lchild);

printf("%3c", ps->data);
print_midtree(ps->rchild);
}
}
void print_posttree(pnode ps)
{
if(ps != NULL)
{
print_posttree(ps->lchild);
print_posttree(ps->rchild);
printf("%3c", ps->data);
}
}
int count_leaf(pnode ps)
{
if(ps != NULL)
{
if(ps->lchild == NULL && ps->rchild == NULL)
count_l++;
count_leaf(ps->lchild);
count_leaf(ps->rchild);
}
return count_l;
}
int count_node(pnode ps)
{
if(ps != NULL)
{
count_n++;
count_node(ps->lchild);
count_node(ps->rchild);
}
return count_n;
}
int count_depth(pnode ps)
{
int ldep, rdep;
if(ps == NULL)
return 0;
else
{
ldep=count_depth(ps->lchild);
rdep=count_depth(ps->rchild);

return ldep>rdep ? (ldep+1) : (rdep+1);
}
}
void main()
{
pnode ps;
ps=create_tree();

printf("pre order.../n");
print_pretree(ps);
printf("/n");
printf("mid order.../n");
print_midtree(ps);
printf("/n");
printf("post order.../n");
print_posttree(ps);
printf("/n");
printf("number of leaf is: %d/n", count_leaf(ps));
printf("number of node is: %d/n", count_node(ps));
printf("max  of  depth is: %d/n", count_depth(ps));
}```

===========================================================

```#include "stdafx.h"
#include <stdlib.h>
#include <malloc.h>
#define DataType char
/**************************************/
/********     树的结构定义     ********/
/**************************************/
struct _tree
{
DataType data;
struct _tree *lchild;
struct _tree *rchild;
};
typedef struct _tree tree, *ptree;
/**************************************/
/********     栈的结构定义     ********/
/**************************************/
struct _node
{
ptree pt;
struct _node *next;
};
typedef struct _node node, *pnode;
struct _stack
{
int size;
pnode ptop;
};
typedef struct _stack stack, *pstack;
/**************************************/
/********     堆的结构定义     ********/
/**************************************/
struct _queue
{
pnode front;
pnode rear;
};
typedef struct _queue queue, *pqueue;
/**************************************/
/********     栈的数据操作     ********/
/**************************************/
pstack init_stack()
{
pnode pn=NULL;
pstack ps=NULL;
pn=(pnode)malloc(sizeof(node));
ps=(pstack)malloc(sizeof(stack));
pn->pt=NULL;
pn->next=NULL;
ps->ptop=pn;
return ps;
}
int empty_stack(pstack ps)
{
if(ps->ptop->next==NULL)
return 1;
else
return 0;
}
void push_stack(pstack ps, ptree pt) /* flag for post tree: 0 for lchild; 1 for rchild */
{
pnode pn=NULL;
pn=(pnode)malloc(sizeof(node));
pn->pt=pt;
pn->next=ps->ptop;
ps->ptop=pn;
}
ptree pop_stack(pstack ps)
{
ptree pt=NULL;
pnode pn=NULL;
if(!empty_stack(ps))
{
pn=ps->ptop;
ps->ptop=ps->ptop->next;
pt=pn->pt;
free(pn);
}
return pt;
}
ptree gettop_stack(pstack ps)
{
if(!empty_stack(ps))
return ps->ptop->pt;
}
/**************************************/
/********     堆的数据操作     ********/
/**************************************/
queue init_queue()
{
pnode pn=NULL;
queue qu;
pn=(pnode)malloc(sizeof(node));
pn->pt=NULL;
pn->next=NULL;
qu.front=qu.rear=pn;
return qu;
}
int empty_queue(queue qu)
{
if(qu.front==qu.rear)
return 1;
else
return 0;
}
void en_queue(queue qu, ptree pt)
{
pnode pn=NULL;
pn=(pnode)malloc(sizeof(node));
pn->pt;
pn->next=qu.rear->next;
qu.rear=pn;
}
ptree de_queue(queue qu)
{
ptree pt=NULL;
pnode pn=NULL;
if(!empty_queue(qu))
{
pn=qu.front;
qu.front=qu.front->next;
pt=pn->pt;
free(pn);
}
return pt;
}
/**************************************/
/********     堆的数据操作     ********/
/**************************************/
ptree init_tree()
{
ptree pt=NULL;
pt=(ptree)malloc(sizeof(tree));
pt->data='0';
pt->lchild=NULL;
pt->rchild=NULL;
return pt;
}
ptree create_tree()
{
char ch;
ptree pt=NULL;

scanf("%c", &ch);
getchar();
if(ch==' ')
return NULL;
else
{
pt=(ptree)malloc(sizeof(tree));
pt->data=ch;
pt->lchild=create_tree();
pt->rchild=create_tree();
}
return pt;
}
void print_pretree(ptree pt)
{
if(pt!=NULL)
{
printf("%3c", pt->data);
print_pretree(pt->lchild);
print_pretree(pt->rchild);
}
}
void print_pretree2(ptree pt)
{
pstack ps=NULL;
ptree p=NULL;
ps=init_stack();
p=pt;
while(p!=NULL || !empty_stack(ps))
{
while(p!=NULL)
{
printf("%3c", p->data);
push_stack(ps, p);
p=p->lchild;
}
if(!empty_stack(ps))
{
p=pop_stack(ps);
p=p->rchild;
}
}
}
void print_midtree(ptree pt)
{
if(pt!=NULL)
{
print_midtree(pt->lchild);
printf("%3c", pt->data);
print_midtree(pt->rchild);
}
}
void print_midtree2(ptree pt)
{
pstack ps=NULL;
ptree p=NULL;
ps=init_stack();
p=pt;
while (p!=NULL || !empty_stack(ps))
{
while(p!=NULL)
{
push_stack(ps, p);
p=p->lchild;
}
if(!empty_stack(ps))
{
p=pop_stack(ps);
printf("%3c", p->data);
p=p->rchild;
}
}
}
void print_posttree(ptree pt)
{
if(pt!=NULL)
{
print_posttree(pt->lchild);
print_posttree(pt->rchild);
printf("%3c", pt->data);
}
}
void print_posttree2(ptree pt)
{
pstack ps=NULL;
ptree p=NULL;
ptree p2=NULL;
ptree lastvisit=NULL;
ps=init_stack();
p=pt;
while (p!=NULL || !empty_stack(ps))
{
while(p!=NULL)
{
push_stack(ps, p);
p=p->lchild;
}
p2=gettop_stack(ps); /* top: rchild==null or sub_root */
if(p2->rchild==NULL || p2->rchild==lastvisit)
{
printf("%3c", p2->data);
lastvisit=pop_stack(ps); /* pop */
}
else
p=p2->rchild;
}
}
int _tmain(int argc, _TCHAR* argv[])
{
ptree pt=NULL;
/*pt=init_tree();*/

printf("Create recursion tree.../n");
pt=create_tree();
/************  recursion ************/
printf("/n/nrecursion...");
printf("/npre tree.../n");
print_pretree(pt);
printf("/nmid tree.../n");
print_midtree(pt);
printf("/npost tree.../n");
print_posttree(pt);
/************  stack ************/
printf("/n/nstack, non recursion...");
printf("/npre tree.../n");
print_pretree2(pt);
printf("/nmid tree.../n");
print_midtree2(pt);
printf("/npost tree.../n");
print_posttree2(pt);
printf("/n");
return 0;
}```

===========================================================

```#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#define OK 1
#define ERROR 0
#define TRUE 1
#define FALSE 0
#define OVERFLOW -2
typedef int status;
typedef struct BiNode
{
char Data;
struct BiNode* lChild;
struct BiNode* rChild;
}BiNode,*pBiNode;
status CreateTree(BiNode** pTree);
status PreOrderTraval(BiNode* pTree);
status InOrderTraval(BiNode* pTree);
status PostOrderTraval(BiNode* pTree);
status Visit(char Data);
status ShowLeaves(BiNode* pTree);
status DelTree(BiNode* pTree);
status Display(BiNode* pTree,int Level);
status Clear(BiNode* pTree);
BiNode *pRoot=NULL;
void main()
{
CreateTree(&pRoot);
printf("/nPreOrder:");
PreOrderTraval(pRoot);
printf("/n");
printf("/nInOrder:");
InOrderTraval(pRoot);
printf("/n");
printf("/nPostOrder:");
PostOrderTraval(pRoot);
printf("/n");
printf("/nShowLeaves:");
ShowLeaves(pRoot);
printf("/n-----------------------/n");
printf("/n");
Display(pRoot,0);
printf("/n");
printf("/nDeleting Tree:/n");
DelTree(pRoot);
printf("BiTree Deleted.");
}
status CreateTree(BiNode** pTree)
{
char ch;
scanf("%c",&ch);
getchar();

if(ch==' ')  /* NOTE: enter space, example: [ab  cd  e  ] */
{
(*pTree)=NULL;
}
else
{
if(!((*pTree)=(BiNode*)malloc(sizeof(BiNode))))
{
exit(OVERFLOW);
}
(*pTree)->Data=ch;
CreateTree(&((*pTree)->lChild));
CreateTree(&((*pTree)->rChild));
}
return OK;
}
status PreOrderTraval(BiNode* pTree)
{
if(pTree)
{
if(Visit(pTree->Data))
{
if(PreOrderTraval(pTree->lChild))
{
if(PreOrderTraval(pTree->rChild))
{
return OK;
}
}
}
return ERROR;
}
else
{
return OK;
}
}
status InOrderTraval(BiNode* pTree)
{
if(pTree)
{
if(InOrderTraval(pTree->lChild))
{
if(Visit(pTree->Data))
{
if(InOrderTraval(pTree->rChild))
{
return OK;
}
}
return ERROR;
}
return ERROR;
}
else
return OK;
}
status PostOrderTraval(BiNode* pTree)
{
if(pTree)
{
if(PostOrderTraval(pTree->lChild))
{
if(PostOrderTraval(pTree->rChild))
{
if(Visit(pTree->Data))
{
return OK;
}
return ERROR;
}
}
return ERROR;
}
else
{
return OK;
}
}
status Visit(char Data)
{
printf("%c",Data);
return OK;
}
status Display(BiNode* pTree,int Level)
{
int i;
if(pTree==NULL)
return FALSE;
Display(pTree->lChild,Level+1);
for(i=0;i<Level-1;i++)
{
printf(" ");
}
if(Level>=1)
{
printf("--");
}
printf("%c/n",pTree->Data);
Display(pTree->rChild,Level+1);
return TRUE;
}
status ShowLeaves(BiNode* pTree)
{
if(pTree)
{
if(ShowLeaves(pTree->lChild))
{
if(ShowLeaves(pTree->rChild))
{
if((pTree->lChild==NULL)&&(pTree->rChild==NULL))
{
if(!Visit(pTree->Data))
{
return ERROR;
}
}
return OK;
}
}
return ERROR;
}
else
{
return OK;
}
}
status DelTree(BiNode* pTree)
{
if(pTree)
{
if(DelTree(pTree->lChild))
{
if(DelTree(pTree->rChild))
{
printf("Deleting %c/n",pTree->Data);
free((void*)pTree);
return OK;
}
}
return ERROR;
}
else
return OK;
} ```

===========================================================

```#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#define OK 1
#define ERROR 0
#define TRUE 1
#define FALSE 0
#define OVERFLOW -2
typedef int status;
typedef struct BiNode
{
char Data;
struct BiNode* lChild;
struct BiNode* rChild;
}BiNode,*pBiNode;
status CreateTree(BiNode** pTree);
status PreOrderTraval(BiNode* pTree);
status InOrderTraval(BiNode* pTree);
status PostOrderTraval(BiNode* pTree);
status Visit(char Data);
status ShowLeaves(BiNode* pTree);
status ShowDepth(BiNode* pTree);
status DelTree(BiNode* pTree);
status Display(BiNode* pTree,int Level);
status Clear(BiNode* pTree);
BiNode *pRoot=NULL;
void main()
{
CreateTree(&pRoot);
printf("/nPreOrder:");
PreOrderTraval(pRoot);
printf("/n");
printf("/nInOrder:");
InOrderTraval(pRoot);
printf("/n");
printf("/nPostOrder:");
PostOrderTraval(pRoot);
printf("/n");
printf("/nShowLeaves:");
ShowLeaves(pRoot);
printf("/nShowDepth:%d/n", ShowDepth(pRoot));
printf("/n------------------/n");
printf("/n");
Display(pRoot,0);
printf("/n");
printf("/nDeleting Tree:/n");
DelTree(pRoot);
printf("BiTree Deleted.");
}
status CreateTree(BiNode** pTree)
{
char ch;
scanf("%c",&ch);
getchar();

if(ch==' ')  /* NOTE: enter space, example: [ab  cd  e  ] */
(*pTree)=NULL;
else
{
if(!((*pTree)=(BiNode*)malloc(sizeof(BiNode))))
exit(OVERFLOW);
(*pTree)->Data=ch;
CreateTree(&((*pTree)->lChild));
CreateTree(&((*pTree)->rChild));
}
return OK;
}
status PreOrderTraval(BiNode* pTree)
{
if(pTree)
{
Visit(pTree->Data);
PreOrderTraval(pTree->lChild);
PreOrderTraval(pTree->rChild);
}
return OK;
}
status InOrderTraval(BiNode* pTree)
{
if(pTree)
{
InOrderTraval(pTree->lChild);
Visit(pTree->Data);
InOrderTraval(pTree->rChild);
}

return OK;
}
status PostOrderTraval(BiNode* pTree)
{
if(pTree)
{
PostOrderTraval(pTree->lChild);
PostOrderTraval(pTree->rChild);
Visit(pTree->Data);
}

return OK;
}
status Visit(char Data)
{
printf("%c",Data);
return OK;
}
status Display(BiNode* pTree,int Level)
{
int i;
if(pTree==NULL)
return FALSE;
Display(pTree->lChild,Level+1);
for(i=0;i<Level-1;i++)
{
printf(" ");
}
if(Level>=1)
{
printf("--");
}
printf("%c/n",pTree->Data);
Display(pTree->rChild,Level+1);
return TRUE;
}
status ShowLeaves(BiNode* pTree)
{
if(pTree)
{
ShowLeaves(pTree->lChild);
ShowLeaves(pTree->rChild);
if((pTree->lChild==NULL)&&(pTree->rChild==NULL))
Visit(pTree->Data);
}

return OK;
}
status ShowDepth(BiNode* pTree)
{
int ldep=0, rdep=0;

if(!pTree)
return 0;
else
{
ldep=ShowDepth(pTree->lChild);
rdep=ShowDepth(pTree->rChild);
return ldep>rdep ? (ldep+1) : (rdep+1);
}
}
status DelTree(BiNode* pTree)
{
if(pTree)
{
DelTree(pTree->lChild);
DelTree(pTree->rChild);
printf("Deleting %c/n",pTree->Data);
free((void*)pTree);
}
return OK;
} ```

===========================================================