C++ N-Queens解决方案C++；

所以我需要帮助解决经典的N皇后问题

运行程序的命令为： nqueens N k-其中N是表格的大小（N x N），k是解决方案的数量

因此，例如，如果我要通过键入nqueens41来运行程序，则会打印出以下内容

_Q__

__uq

Q_uu_u_

__Q_

但是，我不知道如何处理多个解决方案？如何确定此问题的多个解决方案

到目前为止，我掌握的情况如下：

#include <cstdlib>
#include <iomanip>
#include <cmath>
#include <vector>


using namespace std;

class Board
{
private:
    bool** spaces;
    int size;

public:
    Board(int size)
    {
        this->size = size;
        spaces = new bool*[size];
        for (int i = 0; i < size; ++i)
        {
            spaces[i] = new bool[size];
        }
    }

    bool isSafe(int row, int column, vector<int>& state)
    {
       //check row conflict
       //no need to check for column conflicts
       //because the board is beimg filled column
       //by column
       for(int i = 0; i < column; ++i)
       {
          if(state[i] == row)
             return false;
       }

       //check for diagonal conflicts
       int columnDiff = 0;
       int rowDiff = 0;
       for(int i = 0; i < column; ++i)
       {
          columnDiff = abs(column - i);
          rowDiff = abs(row - state[i]);
          if(columnDiff == rowDiff)
             return false;
       }

       return true;

    }

    int getSize()
    {
        return size;
    }

    bool getSpace(int x, int y)
    {
        return spaces[y][x];
    }

    void setSpace(int x, int y, bool value)
    {
        spaces[y][x] = value;
    }

    Board(Board& other)
    {
        this->size = other.getSize();
        spaces = new bool*[size];
        for (int i = 0; i < size; ++i)
        {
            spaces[i] = new bool[size];
            for (int j = 0; j < size; ++j)
            {
                spaces[i][j] = other.getSpace(j, i);
            }
        }
    }

    void backtrack(vector<int>& state, int board_size)
  {
     int row = 0;
     int column = 0;
     bool backtrack = false;

     while(column < board_size)
     {
        while(row < board_size)
        {
           if(backtrack)
           {
              row = state[column] + 1;
              if(row == board_size)
              {
                 column--; //backtrack more
                 backtrack = true;
                 row = 0;
                 break;
              }

              backtrack = false;
           }

           if(isSafe(row, column, state))
           {
              state[column] = row;
              row = 0;
              column++; //advance
              backtrack = false;
              break;
           }

           else
           {
              if(row == (board_size - 1))
              {
                 column--; //backtrack
                 backtrack = true;
                 row = 0;
              }
              else
              {
                 row++;
              }
           }
        }
     }
  }
};

int print_solutions(Board *board, vector<int>& state, int board_size)
{
   for(int i=0; i < board_size; ++i)
   {
      for(int j=0; j < board_size; ++j)
      {
         if(state[i] == j)
            cout << 'Q' << " ";
         else
            cout << '_' << " ";
      }

      cout << endl;
   }
}   

int main(int argc, char* argv[])
{
    if (argc < 2)
    {
        cout << "Usage: nqueens [Board Size] [Number of Solutions]" << endl;
    return 1;
    }

    int board_size = atoi(argv[1]);
    //int solution_count = atoi(argv[2]);
    vector<int> state;
    state.resize(board_size);

    Board *my_board = new Board(board_size);
    my_board->backtrack(state, board_size);

    print_solutions(my_board, state, board_size);

    return 0;
}

#包括
#包括
#包括
#包括
使用名称空间std；
班级委员会
{
私人：
布尔**空间；
整数大小；
公众：
电路板（内部尺寸）
{
这个->大小=大小；
空格=新布尔*[大小]；
对于（int i=0；isize=other.getSize（）；
空格=新布尔*[大小]；
对于（int i=0；icout在这个解决方案中，我保留了大部分原始方法和代码：

#include <cstdlib>
#include <iomanip>
#include <cmath>
#include <vector>
#include <iostream>

using namespace std;

class Board
{
private:
    bool** spaces;
    int size;

public:
    Board(int size)
    {
        this->size = size;
        spaces = new bool*[size];
        for (int i = 0; i < size; ++i)
        {
            spaces[i] = new bool[size];
        }
    }

    bool isSafe(int row, int column, vector<int>& state)
    {
       //check row conflict
       //no need to check for column conflicts
       //because the board is beimg filled column
       //by column
       for(int i = 0; i < column; ++i)
       {
          if(state[i] == row)
             return false;
       }

       //check for diagonal conflicts
       int columnDiff = 0;
       int rowDiff = 0;
       for(int i = 0; i < column; ++i)
       {
          columnDiff = abs(column - i);
          rowDiff = abs(row - state[i]);
          if(columnDiff == rowDiff)
             return false;
       }

       return true;

    }

    int getSize()
    {
        return size;
    }

    bool getSpace(int x, int y)
    {
        return spaces[y][x];
    }

    void setSpace(int x, int y, bool value)
    {
        spaces[y][x] = value;
    }

    Board(Board& other)
    {
        this->size = other.getSize();
        spaces = new bool*[size];
        for (int i = 0; i < size; ++i)
        {
            spaces[i] = new bool[size];
            for (int j = 0; j < size; ++j)
            {
                spaces[i][j] = other.getSpace(j, i);
            }
        }
    }

    bool backtrack(vector<int>& state, int& column, int board_size)
  {
     int row = 0;
     bool backtrack = column == board_size;

     while(column < board_size || backtrack)
     {
        {
           if(backtrack)
           {
              if (column == 0)
                 return false;
              column--;
              row = state[column] + 1;
              if(row == board_size)
              {
                 backtrack = true;
                 continue;
              }

              backtrack = false;
           }

           if(isSafe(row, column, state))
           {
              state[column] = row;
              row = 0;
              column++; //advance
              backtrack = false;
              continue;
           }

           else
           {
              if(row == (board_size - 1))
              {
                 backtrack = true;
              }
              else
              {
                 row++;
              }
           }
        }
     }
     return true;
  }
};

void print_solutions(Board *board, vector<int>& state, int board_size)
{
   for(int i=0; i < board_size; ++i)
   {
      for(int j=0; j < board_size; ++j)
      {
         if(state[i] == j)
            cout << 'Q' << " ";
         else
            cout << '_' << " ";
      }

      cout << endl;
   }
    cout << endl;
}   

int main(int argc, char* argv[])
{
    if (argc < 3)
    {
        cout << "Usage: nqueens [Board Size] [Number of Solutions]" << endl;
    return 1;
    }

    int board_size = atoi(argv[1]);
    int solution_count = atoi(argv[2]);
    vector<int> state;
    state.resize(board_size);

    Board *my_board = new Board(board_size);
    int column = 0;
    while (solution_count-- > 0 && my_board->backtrack(state, column, board_size))
        print_solutions(my_board, state, board_size);

    return 0;
}

#包括
#包括
#包括
#包括
#包括
使用名称空间std；
班级委员会
{
私人：
布尔**空间；
整数大小；
公众：
电路板（内部尺寸）
{
这个->大小=大小；
空格=新布尔*[大小]；
对于（int i=0；isize=other.getSize（）；
空格=新布尔*[大小]；
对于（int i=0；i#include<vector>
using namespace std;

bool intersect(const vector<int> &queens, int x) {
    int y = queens.size();
    for (int i = 0; i < y; i++) {
        if ((abs(queens[i] - x) == 0) || (abs(queens[i] - x) == y - i))
            return true;
    }
    return false;
}

void queensSolution(const int dim, vector<int> queens, vector<vector<int>> &res) {
    if (queens.size() >= dim) {
        res.push_back(queens);
        queens.clear();
        return;
    }
    for (int i = 0; i < dim; i++) {
        if (!intersect(queens, i)) {
            queens.push_back(i);
            queensSolution(dim, queens, res);
            queens.pop_back();
        }
    }
}

int main(){
  int dim = 4;
  vector<int>queens;
  vector<vector<int>> result;
  queensSolution(dim, queens, result);
}