8 Solutions to the Queen's problems

Generally divided into backtracking and full permutation

Fully arranged (recursive)

1#include <iostream>2#include <algorithm>3 4 using namespacestd;5 6Template <size_t n>structArraysizehelper {Char_[n];};7Template <typename T, size_t n> arraysizehelper<n> makearraysizehelper (t (&) [N]);8 #defineArray_size (a) sizeof (Makearraysizehelper (a))9 Ten BOOLValid_permutation (Const int*queen,intlen) One { A     BOOLvalid =true; -  -      for(inti =0; i < Len; ++i) the     { -          for(intj = i +1; J < Len; ++j) -         { -             if(Queen[j]-queen[i] = = J-i | | queen[j]-queen[i] = = i-j) +             { -valid =false; +             } A         } at     } -  -     returnvalid; - } -  - voidPermutation (int*queen,intLenintIdxint&count) in { -     if(idx = =len) to     { +         if(Valid_permutation (queen, Len)) + +count; -     } the     Else *     { $          for(inti = idx; i < Len; ++i)Panax Notoginseng         { - swap (Queen[i], queen[idx]); thePermutation (queen, Len, idx +1, count); + swap (Queen[i], queen[idx]); A         } the     } + } -  $ //Solved by permutation recursion. $ inteightqueen_permutation_recur () - { -     intQueen[] = {0,1,2,3,4,5,6,7 }; the     intCount =0; - WuyiPermutation (Queen, (int) Array_size (Queen),0, count); the  -     returncount; Wu } -  About intMain () $ { -cout << eightqueen_permutation_recur () <<Endl; -  -System"Pause"); A     return 0; +}

Backtracking (Recursive)

#include <iostream>#include<algorithm>using namespacestd;template<size_t n>structArraysizehelper {Char_[n];}; Template<typename T, size_t n> arraysizehelper<n> makearraysizehelper (t (&) [N]);#defineArray_size (a) sizeof (Makearraysizehelper (a))BOOLValid_backtracking (Const int*queen,intLen) {     for(inti =0; i < Len; ++i) {Const intdiff = ABS (queen[i)-Queen[len]); if(diff = =0|| diff = = len-i)return false; }    return true;}voidPlacequeen (int*queen,intLenintIdxint&count) {    if(idx = =Len) {        ++count; }    Else    {         for(inti =0; i < Len; ++i) {Queen[idx]=i; if(valid_backtracking (Queen, idx)) {Placequeen (Queen, Len, idx+1, Count); }        }    }}//Solved by backtracking (DFS) recursion.inteightqueen_backtracking_recur () {intqueen[8]; intCount =0; Placequeen (Queen, (int) Array_size (Queen),0, Count); returncount;}intMain () {cout<< eightqueen_backtracking_recur () <<Endl; System ("Pause"); return 0;}

Reference: http://www.cnblogs.com/codingmylife/archive/2012/10/04/2711839.html

8 Solutions to the Queen's problems