Full array of strings-non-recursive algorithms

The full permutation non-recursive algorithm for strings is to look for sequences that are larger than the previous sequence, such as:

Starting point: The smallest arrangement of the dictionary order, for example 12345

End point: The largest sequence of dictionaries, such as 54321

Procedure: Generates the next permutation of the dictionary order that is just larger than the current arrangement.

Algorithm process: Post-search, small-size, swap, flip

After: The last ascending position in the string I, that is s[k]>s[k+1] (k>i),s[i]<s[i+1];

Find (Small Large): s[i+1...n-1] in the smallest value than AI sj;

Exchange: SI,SJ;

Flip: s[i+1...n-1]

The code is as follows:

  1#include <iostream>2#include <string>3 using namespacestd; 4   5 //Exchange  6 voidSwapChar&AMP;C1,Char&C2)7 {  8     Chartemp =C1; 9C1 =C2;TenC2 =temp; One }  A   - //Flip  - voidReverse_string (string&AMP;STR,int  from,intto ) the {  -      while( from<to ) -     {  -Swap (str[ from+ +], str[to--]);  +     }  - }  +   A //to find the lowest value subscript  at intFind_min (stringStrint  from,intto ) - {  -     CharMin = str[ from];  -     intj = from;  -     if( from==to ) -     {  in         returnJ; -     }  to      for(inti = from+1; I <= to; ++i) +     {  -         //find the smallest value larger than str[from-1]  the         if(Str[i] <= min && str[i] > str[ from-1])  *         {  $Min =Str[i];Panax Notoginsengj =i; -         }  the     }  +     returnJ; A }  the   + voidPermutation_2 (string&AMP;STR,int  from,intto ) - {  $    stringend_str (str); $Reverse_string (END_STR, from, to);  -cout << str <<Endl; -     while(str! =end_str) the    {  -        inti = from; Wuyi        intj =to ; the         while(I! =j) -        {  Wu             if(Str[j-1] <Str[j]) -             {  About                  Break;  $             }  -j--;  -        }  -        intMin =Find_min (str, J, to); ASwap (str[j-1], str[min]);  +reverse_string (str, J, to); thecout << str <<Endl; -    }  $    //Flip Str back .  theReverse_string (str, from, to);  the }  the   the intMainintargcConst Char*argv[]) - {  in     stringstr ="1223";  the     intLen =str.size (); thePermutation_2 (str,0, Len-1);  About     return 0;  the}

Results:

Note: C++stl has integrated next_permutation in the algorithm. You can sort the given string a[0...n-1] first in ascending order, and then call Next_permutation in turn to return false, which completes the non-recursive full permutation algorithm.

Full array of strings-non-recursive algorithms