重建二叉树

ACBFGED ABCDEFG
CDAB CBAD

DBACEGF
BCAD

 
 
#include <iostream>
#include <string.h>
using namespace std;

struct tree
{
    char data;
    tree *left;
    tree *right;
};

tree *converse(char *pos,char *in,int n,int m)
{
    tree *b;
    int k=0;
 char *p,*q,*maxp;
 int maxpost,maxin;
    if(n<=0)
    {
        return NULL;
        
    }
    maxpost=-1;

    for(p=in;p<in+n;p++)
    for(q=pos;q<pos+m;q++)
        if(*p==*q)
        {
            k=q-pos;
            if(k>maxpost)
            {
                maxpost=k;
                maxp=p;
                maxin=p-in;
            }
        }
    
        b=new tree;
        b->data=pos[maxpost];
    
    b->left=converse(pos,in,maxin,m);
    b->right=converse(pos,maxp+1,n-maxin-1,m);
    return b;
}

void pre(tree *b)
{
    if(b)
    {
        cout<<b->data;
        pre(b->left);
        
        pre(b->right);
    }
}

int main()
{
    char c1[1000],c2[1000];
    while(cin>>c1>>c2)
    {
        tree *b;
        b=converse(c1,c2,strlen(c1),strlen(c2));
        pre(b);

        cout<<endl;
    }
    return 0;
}