HDU 1075 What Are You Talking About

#include<iostream>
#include<algorithm>
#include<string>
#include<cstring>
#define xh(a,b,c)for(int a=b;a<=c;a++)
#define dxh(a,b,c)for(int a=b;a>=c;a--)

using namespace std;
struct trie{
int e;
string s;
trie *n[30];
trie(){
e=0;
memset(n,0,sizeof(n));
}
};
trie *h,*p,*q;
string s1,s2,e;
void ins(string a,string b){
p=h;
xh(i,0,b.length()-1){
if(p->n[b[i]-'a']==NULL){
q=new trie;
p->n[b[i]-'a']=q;
}
p=p->n[b[i]-'a'];
}
p->e=1;
p->s=a;
}
void cz(string str){
if(str==""){//从这行开始的连续三行是问题所在
cout<<str;return;
}
p=h;
xh(i,0,str.length()-1){
p=p->n[str[i]-'a'];
if(p==0){
cout<<str;return;}
}
if(p->e)cout<<p->s;
else cout<<str;
}
void xg(string s){
string s2,s3;
if(s==""){
cout<<endl;
return ;
}
xh(i,0,s.length()-1){
s2="";
while(s[i]>='a'&&s[i]<='z')s2+=s[i++];
cz(s2);
cout<<s[i];
}
cout<<endl;
}

int main(){
cin>>s1;
e="END";
h=new trie;
while(cin>>s1&&s1!=e){
cin>>s2;
ins(s1,s2);
}
getline(cin,s1);
getline(cin,s1);
while(1){
getline(cin,s1);
if(s1==e)return 0;
xg(s1);
}
return 0;
}