算法学习(5)----二叉树前序、中序、后序遍历互相转换

 

 

代码：

#include <iostream>
using namespace std;

void BinaryTreeFromInOrderAndPreOrderToPostOrder(char InOrder[],char PreOrder[],int length)
{
    if(length<=0){
        return;
    }
    int rootIndex=0;
    for(;rootIndex<length;rootIndex++){
        if(InOrder[rootIndex]==PreOrder[0])
            break;
    }
    BinaryTreeFromInOrderAndPreOrderToPostOrder(InOrder,PreOrder+1,rootIndex);
    BinaryTreeFromInOrderAndPreOrderToPostOrder(InOrder+rootIndex+1,PreOrder+rootIndex+1,length-rootIndex-1);
    cout<<PreOrder[0];
}

void BinaryTreeFromInOrderAndPostOrderToPreOrder(char InOrder[],char PostOrder[],int length)
{
    if(length<=0){
        return ;
    }
    int rootIndex=0;
    for(;rootIndex<length;rootIndex++){
        if(InOrder[rootIndex]==PostOrder[length-1])
            break;
    }
    cout<<PostOrder[length-1];
    BinaryTreeFromInOrderAndPostOrderToPreOrder(InOrder,PostOrder,rootIndex);
    BinaryTreeFromInOrderAndPostOrderToPreOrder(InOrder+rootIndex+1,PostOrder+rootIndex,length-rootIndex-1);
}

int main(int argc,char* argv[])
{
    char pre[]="GDAFEMHZ";
    char in[]="ADEFGHMZ";
    char post[]="AEFDHZMG";
    cout<<"The original strings are:\n";
    cout<<"Pre:"<<pre<<endl
        <<"In:"<<in<<endl
        <<"Post:"<<post<<endl;

    cout<<"From InOrder And PreOrder To PostOrder:\n";
    BinaryTreeFromInOrderAndPreOrderToPostOrder(in,pre,8);
    cout<<endl;
    cout<<"From InOrder And PostOrder To PreOrder:\n";
    BinaryTreeFromInOrderAndPostOrderToPreOrder(in,post,8);
    cout<<endl;
    return 0;
}