pku1056.txt

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IMMEDIATE DECODABILITY 
Time Limit:1000MS  Memory Limit:10000K
Total Submit:1785 Accepted:844 

Description
An encoding of a set of symbols is said to be immediately decodable if no code for one symbol is the prefix of a code for another symbol. We will assume for this problem that all codes are in binary, that no two codes within a set of codes are the same, that each code has at least one bit and no more than ten bits, and that each set has at least two codes and no more than eight. 

Examples: Assume an alphabet that has symbols {A, B, C, D} 

The following code is immediately decodable: 
A:01 B:10 C:0010 D:0000 

but this one is not: 
A:01 B:10 C:010 D:0000 (Note that A is a prefix of C) 


Input
Write a program that accepts as input a series of groups of records from standard input. Each record in a group contains a collection of zeroes and ones representing a binary code for a different symbol. Each group is followed by a single separator record containing a single 9; the separator records are not part of the group. Each group is independent of other groups; the codes in one group are not related to codes in any other group (that is, each group is to be processed independently). 

Output
For each group, your program should determine whether the codes in that group are immediately decodable, and should print a single output line giving the group number and stating whether the group is, or is not, immediately decodable.

Sample Input


01
10
0010
0000
9
01
10
010
0000
9


Sample Output


Set 1 is immediately decodable
Set 2 is not immediately decodable
 


Source
Pacific Northwest 1998


Source

Problem Id:1056  User Id:Drizzle 
Memory:200K  Time:0MS
Language:G++  Result:Accepted

Source 

/*
   农夫三拳@seu
   drizzlecrj.gmail.com
   2007-03-02
*/
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

typedef vector<string> STR_VEC;

bool Judge(const STR_VEC& words)
{
	int size = words.size();
	int i, j;
	for(i = 0; i < size; ++i)
	{
		for(j = 0; j < size; ++j)
		{
			if(i != j && search(words[i].begin(), words[i].end(),words[j].begin(), words[j].end()) == words[i].begin())
				return false;
		}
	}
	return true;
}

int main()
{
	STR_VEC words;
	string word;
	int t = 1;
	while(cin >> word)
	{
		if(word == "9")
		{
			if(Judge(words))
				cout << "Set " << t++ << " is immediately decodable" << endl;
			else
				cout << "Set " << t++ << " is not immediately decodable" << endl;
			words.clear();
		}
		else
		{
			words.push_back(word);
		}
	}

	return 0;
}