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分享【急！！】求高手关于Huffman Codes的一道程序题
有关huffman code的一道程序题：
给出各个字符的权重，再给出各个字符的一组编码，判断给定的编码是不是正确的huffman编码
原题如下：
In 1953, David A. Huffman published his paper “A Method for the Construction of Minimum-Redundancy Codes”, and hence printed his name in the history of computer science. As a professor who gives the final exam problem on Huffman codes, I am encountering a big problem: the Huffman codes are NOT unique. For example, given a string “aaaxuaxz”, we can observe that the frequencies of the characters 'a', 'x', 'u' and 'z' are 4, 2, 1 and 1, respectively. We may either encode the symbols as {'a'=0, 'x'=10, 'u'=110, 'z'=111}, or in another way as {'a'=1, 'x'=01, 'u'=001, 'z'=000}, both compress the string into 14 bits. Another set of code can be given as {'a'=0, 'x'=11, 'u'=100, 'z'=101}, but {'a'=0, 'x'=01, 'u'=011, 'z'=001} is NOT correct since “aaaxuaxz” and “aazuaxax” can both be decoded from the code 00001011001001. The students are submitting all kinds of codes, and I need a computer program to help me determine which ones are correct and which ones are not.
Input Specification:
Your program must read test cases from a file “input.txt”. The input file consists of several test cases. For each test case, the first line gives an integer N (63), then followed by a line that contains all the N distinct characters and their frequencies in the following format:
c[1] f[1] c[2] f[2] ... c[N] f[N]
where c[i] is a character chosen from {'0' - '9', 'a' - 'z', 'A' - 'Z', '_'}, and f[i] is the frequency of c[i] and is an integer no more than 1000. The next line gives an integer M (1000), then followed by M student submissions. Each student submission consists of N lines, each in the format:
c[i] code[i]
where c[i] is the i-th character and code[i] is a string of '0's and '1's.
The input ends with N being 0, and that case must NOT be processed.
Output Specification:
For each test case, output to a file “output.txt”. First print in a line "Case #:" where # is the case number starting from 1. Then in the following M lines, either print “Yes” if the student’s submission is correct, or “No” if not.
Sample Input:
4
a 4 x 2 u 1 z 1
2
a 0
x 10
u 110
z 111
a 0
x 01
u 011
z 001
7
A 1 B 1 C 1 D 3 E 3 F 6 G 6
2
A 00000
B 00001
C 0001
D 001
E 01
F 10
G 11
A 000
B 001
C 010
D 011
E 100
F 101
G 110
0
Sample Output:
Case 1:
Yes
No
Case 2:
Yes
No
刚学数据结构不久，请各位大虾帮帮忙
高手给个程序代码（c语言）吧，给个快捷可行的算法或伪代码也可以～～
给出各个字符的权重，再给出各个字符的一组编码，判断给定的编码是不是正确的huffman编码
原题如下：
In 1953, David A. Huffman published his paper “A Method for the Construction of Minimum-Redundancy Codes”, and hence printed his name in the history of computer science. As a professor who gives the final exam problem on Huffman codes, I am encountering a big problem: the Huffman codes are NOT unique. For example, given a string “aaaxuaxz”, we can observe that the frequencies of the characters 'a', 'x', 'u' and 'z' are 4, 2, 1 and 1, respectively. We may either encode the symbols as {'a'=0, 'x'=10, 'u'=110, 'z'=111}, or in another way as {'a'=1, 'x'=01, 'u'=001, 'z'=000}, both compress the string into 14 bits. Another set of code can be given as {'a'=0, 'x'=11, 'u'=100, 'z'=101}, but {'a'=0, 'x'=01, 'u'=011, 'z'=001} is NOT correct since “aaaxuaxz” and “aazuaxax” can both be decoded from the code 00001011001001. The students are submitting all kinds of codes, and I need a computer program to help me determine which ones are correct and which ones are not.
Input Specification:
Your program must read test cases from a file “input.txt”. The input file consists of several test cases. For each test case, the first line gives an integer N (63), then followed by a line that contains all the N distinct characters and their frequencies in the following format:
c[1] f[1] c[2] f[2] ... c[N] f[N]
where c[i] is a character chosen from {'0' - '9', 'a' - 'z', 'A' - 'Z', '_'}, and f[i] is the frequency of c[i] and is an integer no more than 1000. The next line gives an integer M (1000), then followed by M student submissions. Each student submission consists of N lines, each in the format:
c[i] code[i]
where c[i] is the i-th character and code[i] is a string of '0's and '1's.
The input ends with N being 0, and that case must NOT be processed.
Output Specification:
For each test case, output to a file “output.txt”. First print in a line "Case #:" where # is the case number starting from 1. Then in the following M lines, either print “Yes” if the student’s submission is correct, or “No” if not.
Sample Input:
4
a 4 x 2 u 1 z 1
2
a 0
x 10
u 110
z 111
a 0
x 01
u 011
z 001
7
A 1 B 1 C 1 D 3 E 3 F 6 G 6
2
A 00000
B 00001
C 0001
D 001
E 01
F 10
G 11
A 000
B 001
C 010
D 011
E 100
F 101
G 110
0
Sample Output:
Case 1:
Yes
No
Case 2:
Yes
No
刚学数据结构不久，请各位大虾帮帮忙
高手给个程序代码（c语言）吧，给个快捷可行的算法或伪代码也可以～～
...全文
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jiedong_zju 2008-12-14
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ll千秋万载，一统江湖
桌球控 2008-12-12
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姥姥好强大
jerry4966263 2008-12-11
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悲剧啊..
sleepwater 2008-12-11
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[Quote=引用 1 楼 iamtheteacher 的回复:]
姥姥告诉你: 这种行为是可耻的 -_-! 我会监视这个版面, 并且通告全体老师, 有发现跟这里提供的代码相似者, 0分没商量.
CYLL
[/Quote]
CYLL 我错了，本想求个算法而已。
不过现在自己已经编完了了～～
姥姥告诉你: 这种行为是可耻的 -_-! 我会监视这个版面, 并且通告全体老师, 有发现跟这里提供的代码相似者, 0分没商量.
CYLL
[/Quote]
CYLL 我错了，本想求个算法而已。
不过现在自己已经编完了了～～
fenix124 2008-12-10
- 打赏
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悲剧阿
zzhxlyc 2008-12-10
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悲剧啊！
isilent 2008-12-09
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悲剧～
GetOverMVP 2008-12-09
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悲剧啊
clocy 2008-12-09
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lz太xe了...
ratehk 2008-12-09
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赞姥姥～
jacobgao 2008-12-09
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悲剧啊！赞姥姥～
iamtheteacher 2008-12-09
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姥姥告诉你: 这种行为是可耻的 -_-! 我会监视这个版面, 并且通告全体老师, 有发现跟这里提供的代码相似者, 0分没商量.
CYLL
CYLL
