SDUT 2136 数据结构实验之二叉树的建立与遍历

 题目链接：http://acm.sdut.edu.cn/sdutoj/problem.php?action=showproblem&problemid=2136

  这个题看书+问学长.2A.

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

int num=-1;

char str[51];

struct tree

{

    char  lat;

    struct tree *left;

    struct tree *right;

};

struct tree *build()//建树

{

    struct tree *p;

    num++;

    if(str[num]==',')

    return NULL;

    p = (struct tree *)malloc(sizeof(struct tree));

    p -> lat = str[num];

    p -> left = build();

    p -> right = build();

    return p;

}

void  midshow(struct tree *k)//中序

{

   if(k)

   {

       midshow(k -> left);

       printf("%c",k -> lat);

       midshow(k -> right);

   }

   else return ;

}

void downshow(struct tree *k)//后序

{

    if(k)

    {

        downshow(k -> left);

        downshow(k -> right);

        printf("%c",k -> lat);

    }

}

int count(struct tree *k)//记录叶子节点

{

    if(k)

    {

     if(k -> right == NULL && k -> left == NULL)

     return 1;

     else

     {

         return count(k -> right)+count(k -> left);

     }

    }

    else

    return 0;

}

int depth(struct tree *k)//记录深度

{

    int m,n;

    if(k == NULL)

    return 0;

    else

    {

        m = depth(k -> left);

        n = depth(k -> right);

        if(m > n)

        return m+1;

        else

        return n+1;

    }

}

int main()

{

    struct tree *head;

    int i,j;

    scanf("%s",str);

    head = build();

    midshow (head);

    printf("\n");

    downshow (head);

    printf("\n");

    i = count(head);

    printf("%d\n",i);

    j = depth(head);

    printf("%d\n",j);

    return 0;

}