n 个对象的排列（重复排列）

Question

我正在寻找“排列”算法（重复排列）的快速实现。 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。
示例：

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，使用 C、C# 或 Pascal 编写代码）

提前致谢
菲利普

Answer 1

如果可以使用 C++，标准库中已经提供：

#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：这个的输出是：

AAAABCC 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 ACBAA 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

对于不会使用 C++ 的任何人，Mark Nelson 几年前在 C/C++ 用户日志中写了一个 article，这可能会有所帮助。