Question

我试图弄清楚如何根据给定的字符串生成C ++中的单词列表（类似于crunch wordlist的工作方式）

我是C ++的新手，只是让程序一次列出一个字符。

我一直在网上搜索相当一段时间没有太多运气，除了找到O（n ^ 2）并没有太多想法如何将它实现到程序中。

代码：

int main() {
    string characters = "abcde";

    int length = 5;
    string word = "";
    for(int i = word.length(); i <= length; i++) {
        for(int l = 0; l < characters.length(); l++) {
            word += characters[l];
            cout << word << "\n";
        }
    }
    return 0;
}

结果：

a
b
c
d
e

通缉结果：http://pastebin.com/tgyUtKfA

结果片段：

a
b
c
d
e
aa
ab
ac
ad
ae
ba
bb
bc
bd
be
ca
cb
cc
cd
ce
da
db
dc
dd
de
ea
eb
ec
ed
ee
aaa

（最终结果遵循该模式，直到＆＃34; eeeee＆＃34;）

Answer 1

#include <string>
#include <vector>
#include <iostream>
using namespace std;

vector<string> make_permutations(int length) {
  if (length == 0) {
    return vector<string>{};
  }
  vector<string> results;
  vector<string> children = make_permutations(length - 1);
  for (char letter = 'a'; letter <= 'z'; letter++) { 
    results.emplace_back(1, letter);
    for(auto child : children) {
      results.push_back(std::string(1, letter) + child);
    }
  }
  return results;
}

int main()
{
 auto results = make_permutations(2);
    for(auto s : results) cout << s << endl;
}

直播：http://melpon.org/wandbox/permlink/gGVAxbVUFVZs4fUR

Answer 2

// dyndict.cpp

#include <iostream>
#include <string>
#include <vector>
#include <mutex>

using namespace std;

class CDynDict
{
public:
    CDynDict();
    ~CDynDict();

    void Reset(const string& source, int minout, int maxout);
    bool Next(string& str);

private:
    string _source;
    int _outlen, _minout, _maxout;
    vector<int> _vecdict;
    mutex _mutex;
};

CDynDict::CDynDict()
{
}

CDynDict::~CDynDict()
{
}

void CDynDict::Reset(const string& source, int minout, int maxout)
{
    unique_lock<mutex> locker(_mutex);
    _source = source;
    _minout = minout;
    _maxout = maxout;   
    if (_minout > _maxout)
        swap(_minout, _maxout);
    _outlen = minout;
    _vecdict.resize(_outlen);
}

bool CDynDict::Next(string& str)
{
    int i = 0, carry = 1; 
    int lsrc = _source.length();
    unique_lock<mutex> locker(_mutex);

    if (_vecdict.size() == 0 || _outlen > _maxout)
        return false;

    str.clear();
    while (i <_outlen) str += _source[_vecdict[i++]];

    for (i = _outlen-1; i >= 0; i--)
    {   
        if (carry == 0) break;
        _vecdict[i] += carry;
        carry = _vecdict[i] / lsrc;
        if (carry > 0 && i > 0) _vecdict[i] %= lsrc;
    }       

    if (_vecdict[0] >= lsrc)
    {   
        _vecdict.resize(++_outlen);
        _vecdict.assign(_outlen, 0);
    }       
    return true;
}


int main(int argc, char* argv[])
{
    CDynDict dict;
    string str;

    dict.Reset("abcde", 1, 4);

    while (dict.Next(str))
        cout << str << endl;

    return 0;
}

用C ++生成一个词表

2 个答案: