Immediate Decodability

Immediate Decodability

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 a data file. 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.

The Sample Input describes the examples above.

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

HINT

//（如果任意一個串，均不是其它串的前綴則表明，is immediately decodable，否則is not immediately decodable）

#include
#include
int main()
{
	char a[100][100];
	int t=0,i,j,t1,t2,k,s=1;
	while(gets(a[t]))
	{
		t++;
		while(gets(a[t]))
		{
			if(a[t][0]=='9')
				break;
			t++;
		}
		for(i=0;i
 //參考他人代碼
單模式匹配算法：給定一個單詞和一個字符串，查看字符串中是否存在該單詞，通過調用strstr函數進行匹配；
#include
#include
#include
#include
 
using namespace std ;
 
int main()  
{
    char word[1000][20] ;
    int t = 1 ;
    while(cin >> word[0])  
	{
        int i = 1 ;
        while(cin >> word[i++])
            if(strcmp(word[i-1],"9")==0)
                break ;
        bool flag = true ;
        i--;
        for(int j = 0 ; j < i ; j++)//每一行均與其它進行比較 
		{
            char *p = NULL ;
            for(int k = 0 ; k < i ; k++)    
			{
                if(j == k)
                    continue ;
                p = strstr(word[j],word[k]) ;//第j行在其它行（k）中遍歷，看是否是其前綴。
                 if(p == word[j]) 
	      {
                    flag = false ;
                    break ;
                }
            }
            if(flag == false)
                break ;
        }
        if(flag)
            printf("Set %d is immediately decodable\n",t++) ;
        else
            printf("Set %d is not immediately decodable\n",t++) ;
	}
    return 0 ;
}