C#组合函数

using System; using System.Collections.Generic; using System.Text; namespace ConsoleApplication1 { class Class1 { static string[] str = { "A", "B", "C", "D", "E" }; static void Main() { Dictionary<string, int> dic = new Dictionary<string, int>(); //将数组元素添加到dic for (int i = 0; i < str.Length; i++) { dic.Add(str[i], i); } GetDic(dic); Console.ReadLine(); } static void GetDic(Dictionary<string, int> dd) { Dictionary<string, int> dic = new Dictionary<string, int>(); //主要是抓住AB,AC,AD,AE,然后就是开始从 BC，BD这样的原理用dd中的键与数组的中对应索引比dd中的value大进行组合 foreach (KeyValuePair<string, int> kk in dd) { for (int i = kk.Value + 1; i < str.Length; i++) { Console.WriteLine(kk.Key + str[i]); dic.Add(kk.Key + str[i], i); } } //递归 if (dic.Count > 0) GetDic(dic); } } } 结果 AB AC AD AE BC BD BE CD CE DE ABC ABD ABE ACD ACE ADE BCD BCE BDE CDE ABCD ABCE ABDE ACDE BCDE ABCDE