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> using namespace std;       typedef struct BinaryTree     {     char data;     BinaryTree* lchild;     BinaryTree* rchild; }BinaryTree;   void RebuildTree(BinaryTree* &Tree,char* pre,char* in,int len)     {     Tree = (BinaryTree*)malloc(sizeof(BinaryTree));     if(Tree!=NULL)         {         if(len<=0)             {//递归截止条件             Tree = NULL;             return ;         }         int index = 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 ; }   void PostOrderTravese(BinaryTree* Tree)     {//后序遍历输出     if(Tree==NULL)         return;     PostOrderTravese(Tree->lchild);     PostOrderTravese(Tree->rchild);     printf("%c",Tree->data); }     int main() {     char pre[101];     char in[101];     while(scanf("%s %s",pre,in)!=EOF)         {         BinaryTree* tree;         int length = strlen(pre);         RebuildTree(tree,pre,in,length);            PostOrderTravese(tree);         cout<<endl;     }     return 0; }