E – 求二叉树的层次遍历

```cpp
#include<bits/stdc++.h>
using namespace std;
struct node
{
char data;
node *lchild;
node *rchild;
};
node *creat(char first[],char mid[],int len)
{
if(len<=0)
return NULL;
node *t = new node();
t->data = first[0];
int i;
for(i=0;i<len;i++)
{
if(mid[i]==first[0])
break;
}
t->lchild = creat(first+1,mid,i);
t->rchild = creat(first+i+1,mid+i+1,len-i-1);
return t;
}
void cengxu(node *t)
{
node *temp[110];
int in=0,out=0;
temp[in++]=t;
while(in>out)
{
if(temp[out])
{
cout<<temp[out]->data;
temp[in++]=temp[out]->lchild;
temp[in++]=temp[out]->rchild;
}
out++;
}
}
int main()
{
int t;
char first[100],mid[100];
cin>>t;
while(t–)
{
cin>>first>>mid;
int len = strlen(first);
node *root = new node();
root = creat(first,mid,len);
cengxu(root);
cout<<endl;
}
return 0;
}