n个对象的排列(具有重复的排列)

Question

我正在寻找"排列"算法的快速实现(具有重复的排列).给定N个对象(数量a中的A,数量b中的B,......),生成所有可能的组合.
例:

Arrangement("AAA", "B", "CC") would return :   
"AAABCC" "AABACC" "AABCAC" "AABCCA" "ABAACC" "ABACAC" "ABACCA" "ABCAAC"   
"ABCACA" "ABCCAA" "BAAACC" "BAACAC" "BAACCA" "BACAAC" "BACACA" "BACCAA"   
"BCAAAC" "BCAACA" "BCACAA" "BCCAAA" "AAACBC" "AACABC" "AACBAC" "AACBCA"   
"ACAABC" "ACABAC" "ACABCA" "ACBAAC" "ACBACA" "ACBCAA" "CAAABC" "CAABAC"   
"CAABCA" "CABAAC" "CABACA" "CABCAA" "CBAAAC" "CBAACA" "CBACAA" "CBCAAA"   
"AAACCB" "AACACB" "AACCAB" "AACCBA" "ACAACB" "ACACAB" "ACACBA" "ACCAAB"   
"ACCABA" "ACCBAA" "CAAACB" "CAACAB" "CAACBA" "CACAAB" "CACABA" "CACBAA"   
"CCAAAB" "CCAABA" "CCABAA" "CCBAAA"  

(如果可能,用C,C#或Pascal编码)

在此先感谢
Philippe

Answer 1

如果您可以使用C++,它已经在标准库中提供:

#include <algorithm>
#include <string>
#include <iostream>

int main() { 
    std::string a("AAABCC");

    do {
        std::cout << a << "\t";
    } while (std::next_permutation(a.begin(), a.end()));
    return 0;
}

编辑:这个输出是:

AAABCC AAACBC AAACCB AABACC AABCAC AABCCA AACABC AACACB AACBAC AACBCA AACCAB AACCBA ABAACC ABACAC ABACCA ABCAAC ABCACA ABCCAA ACAABC ACAACB ACABAC ACABCA ACACAB ACACBA ACBAAC ACBACA ACBCAA ACCAAB ACCABA ACCBAA BAAACC BAACAC BAACCA BACAAC BACACA BACCAA BCAAAC BCAACA BCACAA BCCAAA CAAABC CAAACB CAABAC CAABCA CAACAB CAACBA CABAAC CABACA CABCAA CACAAB CACABA CACBAA CBAAAC CBAACA CBACAA CBCAAA CCAAAB CCAABA CCABAA CCBAAA

对于任何不能使用C++的人来说,Mark Nelson 几年前在C/C++用户期刊上写了一篇可能有用的文章.