http://poj.org/problem?id=2138
#include <iostream>
#include <string>
#include <vector>
#include <cstring>
#include <algorithm>
using namespace std;
int D;
string ori;
string v[1005];
int l[1005];
int longgest;
bool visited[1005];
vector<string> vre;
void search(string &str,int z)
{
bool Find = false;
visited[z] = true;
for(int i = 1;i <= D;i++)
{
if(l[i] == l[z] + 1)
{
string::size_type index = 0;
bool lost = false;
for(int j = 0;j < l[z];j++)
{
index = v[i].find(str[j],index);
if(index == string::npos)
{
lost = true;
}
index++;
}
if(!lost)
{
if(!visited[i])
{
search(v[i],i);
}
Find = true;
}
}
}
if(!Find)
{
vre.push_back(str);
}
}
int main()
{
while(cin>>D)
{
cin>>v[0];
l[0] = v[0].size();
vre.clear();
longgest = 0;
memset(visited,0,sizeof(visited));
for(int i = 1;i <= D;i++)
{
cin>>v[i];
l[i] = v[i].size();
}
search(v[0],0);
int length = 0;
int pos = 0;
for(int i = 0;i < vre.size();i++)
{
if(vre[i].size() > length)
{
length = vre[i].size();
pos = i;
}
}
//cout<<endl;
cout<<vre[pos]<<endl;
}
return 0;
}
/*
Travel Games
Time Limit: 3000MS Memory Limit: 65536K
Total Submissions: 1850 Accepted: 647
Description
The cows are taking a trip to the lakes in Minnesota. Like everyone else, they are bored and are playing "travel games" to pass the time away.
In this travel game, the first cow thinks of a three letter word from the Sacred Travel Game Dictionary (STGD). The next cow in line must add a letter to the word (at the beginning, between two letters, or at the end) to make another word in the STGD. The cows are curious as to just how big the final word can be.
Given a dictionary of D (1 <= D <= 1000) words and a starting word, find any of the longest possible words that can be formed playing this travel game.
Input
* Line 1: The integer D followed by a space followed by a legal three letter word.
* Line 2 through D+1: Each line contains a legal word no longer than 80 characters, consisting only of lowercase letters, from the STGD.
Output
A single line with the longest word that can be formed by extending the input seed.
The input ensure the correct result will be unique.
Sample Input
9 cal
cal
calf
calfs
call
calls
choral
chorale
coal
coral
Sample Output
chorale
Hint
[From the sequence: cal, coal, coral, choral, chorale]
*/
