I think that I am right,
but I WAed

#include<iostream>
#include<string>
#define maxn 26
using namespace std;
string line[maxn][maxn];
int pos,store[maxn];
int n,_count,_tot;
int degree[2][maxn],st;
int adj[maxn][maxn];
bool check(){
	int a,b,c;
	a=b=0;
	for (int i=0;i<maxn;++i){
		if (degree[0][i]-degree[1][i]==1){
			++a;
			st=i;
		}
		else if (degree[0][i]-degree[1][i]==-1)
			++b;
		else if (degree[0][i]==degree[1][i])
			++c;
		else return false;
	}
	if (a==1&&b==1)
		return true;
	if (a==0&&b==0)
		return true;
	return false;
}
bool fluery(int dep,int v){
	bool tmp;
	if (dep==n)
		return true;
	for (int i=0;i<=25;++i)
		if (adj[v][i]){
	    	--adj[v][i];
			store[pos++]=i;
			if (fluery(dep+1,i))
				return true;
	    	++adj[v][i];
			--pos;
		}
	return false;
}
void output(){
	int p=1;
	cout<<line[store[0]][store[1]];
	for (int i=1;i<n;++i){
		cout<<"."<<line[store[p]][store[p+1]];
		++p;
	}
	cout<<endl;
}
void work(){
	string s;
	cin>>n;
	for (int i=0;i<n;++i){
		cin>>s;
		line[s[0]-'a'][s[s.size()-1]-'a']=s;
		++adj[s[0]-'a'][s[s.size()-1]-'a'];
		++degree[0][s[0]-'a'];
		++degree[1][s[s.size()-1]-'a'];
	}
	if (check()){
		store[0]=st;
		pos=1;
		fluery(0,st);
		output();
	}
	else cout<<"***"<<endl;
}
int main (void){
	int t;
	cin>>t;
	while (t){
	    work();
		--t;
	}
	return 0;
}

• Re:For Help,WA 2337 (24) 695375900 2010-06-26 23:49:58
  • Re:For Help,WA 2337 (42) Practice_Scott 2012-08-17 20:08:51