UVa 644 - Immediate Decodability

最新推荐文章于 2021-07-28 19:02:08 发布

原创最新推荐文章于 2021-07-28 19:02:08 发布 · 316 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#字符串

UVa 专栏收录该内容

33 篇文章

订阅专栏

本文探讨了即时可解码编码的概念，即一种确保没有一个符号的编码是另一个符号编码的前缀的方法。通过示例说明了即时可解码与非即时可解码编码的区别，并提供了一个用于检测一组编码是否即时可解码的程序实现。

Immediate Decodability

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 ofC)

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

Sample Output

Set 1 is immediately decodable
Set 2 is not immediately decodable

Miguel A. Revilla
2000-01-17

#include<stdio.h>
#include<string.h>
int main()
{
    int i=0,j,k,n=1;
    char s[10][12];
    while(scanf("%s",s[i])!=EOF)
    {
        int flag=1;
        if(s[i][0]=='9')
        {
            for(j=0;j<i&&flag==1;j++)
                for(k=0;k<i&&flag==1;k++)
                {
                    if(j!=k&&strlen(s[j])<=strlen(s[k]))
                        if(&s[k][0]==strstr(s[k],s[j]))
                        flag=0;
                }
            i=0;
            if(flag)
                printf("Set %d is immediately decodable\n",n);
            else
                printf("Set %d is not immediately decodable\n",n);
            n++;
        }
        else
            i++;
    }
    return 0;
}