Two common ways to enumerate permutations

1. Recursive enumeration

1#include <iostream>2 using namespacestd;3 4 voidPrint_permutation (intNint*p,intcur)5 {6     if(cur = =N)7     {8          for(inti =0; I < n; i++)9cout <<P[i];Tencout <<Endl; One     } A     Else  for(inti =1; I <= N; i++) -     { -         intOK =1; the          for(intj =0; J < cur; J + +) -         if(P[j] = = i) OK =0; -         if(OK) -         { +P[cur] =i; -Print_permutation (n, p, cur +1); +         } A     } at } - int_tmain (intARGC, _tchar*argv[]) - { -     intn,p[10000],cur=0; -CIN >>N; - print_permutation (n, p, cur); in     return 0; -}

2, Stl--next_permutation

1#include <iostream>2#include <algorithm>3 using namespacestd;4 5 int_tmain (intARGC, _tchar*argv[])6 {7     intN, p[Ten];8CIN >>N;9      for(inti =0; I < n; i++)TenCIN >>P[i]; OneSort (p, p +n); A      Do{ -          for(inti =0; I < n; i++) -cout <<P[i]; thecout <<Endl; -} while(Next_permutation (p, p +n)); -     return 0; -}

Two common ways to enumerate permutations