已知前序中序求后续




#include<stdio.h>

#include<string.h>

charpre[26];

charin[26];

charpost[26];

        /**三个low和high分别是pre，in和post的起止位置*/

voidPost(intlow1,inthigh1,intlow2,inthigh2,intlow,inthigh)

{

    if(low>high) return;

    charc=pre[low1];

    post[high]=c;   /**把pre[]第一个字符赋给post[]最后一个位置*/

    intk=0;

    while(in[low2+k]!=c)    /**找到pre[]第一个字符在in[]中的位置*/

        k++;

    Post(low1+1,low1+k,low2,low2+k-1,low,low+k-1);

    Post(low1+k+1,high1,low2+k+1,high2,low+k,high-1);

    return;

}

 

intmain()

{

    while(scanf("%s",pre)!=EOF)

    {

        scanf(" %s",in);

        intlen=strlen(pre);

        Post(0,len-1,0,len-1,0,len-1);

        printf("%s",post);

        printf("\n");

    }

    return0;

}
















#include <iostream>

#include <cstring>

usingnamespace std;

 

 

 

typedefstruct BinaryTree

    {

    chardata;

    BinaryTree* lchild;

    BinaryTree* rchild;

}BinaryTree;

 

voidRebuildTree(BinaryTree* &Tree,char* pre,char* in,intlen)

    {

    Tree = (BinaryTree*)malloc(sizeof(BinaryTree));

    if(Tree!=NULL)

        {

        if(len<=0)

            {//递归截止条件

            Tree = NULL;

            return;

        }

        intindex = 0;

        while(index<len&&*(pre)!=*(in+index))

            {//寻找当前的root结点（包含子树）

            index++;

        }

        Tree->data = *(pre);

        RebuildTree(Tree->lchild,pre+1,in,index);//去掉root结点

        RebuildTree(Tree->rchild,pre+1+index,in+1+index,len-(index+1));//去掉左边和根节点

    }

    return;

}

 

voidPostOrderTravese(BinaryTree* Tree)

    {//后序遍历输出

    if(Tree==NULL)

        return;

    PostOrderTravese(Tree->lchild);

    PostOrderTravese(Tree->rchild);

    printf("%c",Tree->data);

}

 

 

intmain()

{

    charpre[101];

    charin[101];

    while(scanf("%s %s",pre,in)!=EOF)

        {

        BinaryTree* tree;

        intlength = strlen(pre);

        RebuildTree(tree,pre,in,length);   

        PostOrderTravese(tree);

        cout<<endl;

    }

    return0;

}