逻辑来选择从笛卡尔集一组特定的 [英] Logic to select a specific set from Cartesian set

问题描述

我正在做一个密码暴力破解工具，作为一个学习锻炼，我希望它是可恢复的。

所以，我要的是要能够说，这是一组可能的字符，如果我计算笛卡尔集此每个可能的组合的设置长度为n，什么是该组点x

不过，我想这样做，不计算整个集合。我已经看到了同样的逻辑在一个地方在线，但我无法推广为适应。

任何帮助将是非常美妙的，谢谢！我很精通C＃有没有什么帮助。

编辑：这是我刚才提到的问题：的如何选择笛卡尔积特定项目不计算其他所有项

编辑：这里是我的意思的例子：

 字符集= [ ABCD] 
 
长度为n = 4 
 
置换：
 
 [AAAA] 
 [AAAB] 
 [AAAC] 
〔AAAD] 
 [AABA] 
 .... 
 [DDDD] 
  

所以，如果我在4搜索的集合，我会得到[AAAD。但是，如果我在寻找7000元，那么它需要较长的时间才能到这一点。

解决方案

这实现了回答您链接的问题：

 静态字符串获取（串字符，整数N，int i）以
 {
串RET =; 
 INT尺寸= 1; 
为（INT J = 0; J< N; J ++）{$​​ B $ B RET =字符[（I /尺寸）％chars.Length] + RET; 
尺寸* = chars.Length; 
} 
返回RET; 
} 
  

例如：

 字符串的字符=ABCD; 
 INT N = 3; 
 
的for（int i = 0; I< Math.Pow（chars.Length，N）;我++）
 Console.WriteLine（我+\t+获取（字符，N，I））; 
  

  0 AAA 
 1分配AAB 
 2 AAC 
 3 AAD 
 ... 
 61 DDB 
 62 DDC 
 63 DDD 
  

I'm making a password brute forcing tool as a learning exercise, and I want it to be resumable.

So, what I want is to be able to say, this is the set of possible characters, if I computed the Cartesian set of every possible combination of this set up to length n, what is the set at point x?

However, I want to do this without computing the entire set. I've seen similar logic in one place online but I was unable to generalise this to fit.

Any help would be fantastic, thanks! I'm fluent in C# if that helps.

Edit: Here's the question I mentioned earlier: How to select specific item from cartesian product without calculating every other item

Edit: here's an example of what I mean:

Char set = [abcd]

Length n = 4

Permutations:

[aaaa]
[aaab]
[aaac]
[aaad]
[aaba]
....
[dddd]

So if I'm searching for the set at 4, I'd get [aaad]. But if I'm searching for element 7000, then it takes a long time to get to that point.

解决方案

This implements the answer to the question you link:

static string Get(string chars, int n, int i)
{
    string ret = "";
    int sizes = 1;
    for (int j = 0; j < n; j++) {
        ret = chars[(i / sizes) % chars.Length] + ret;
        sizes *= chars.Length;
    }
    return ret;
}

Example:

string chars = "abcd";
int n = 3;

for (int i = 0; i < Math.Pow(chars.Length, n); i++)
    Console.WriteLine(i + "\t" + Get(chars, n, i));

0       aaa
1       aab
2       aac
3       aad
...
61      ddb
62      ddc
63      ddd

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