RosettaCodeData/Task/N-queens-problem/C++/n-queens-problem-3.cpp

101 lines
2.9 KiB
C++

#include <windows.h>
#include <iostream>
#include <string>
//--------------------------------------------------------------------------------------------------
using namespace std;
//--------------------------------------------------------------------------------------------------
class point
{
public:
int x, y;
point(){ x = y = 0; }
void set( int a, int b ){ x = a; y = b; }
};
//--------------------------------------------------------------------------------------------------
class nQueens
{
public:
void solve( int c )
{
_count = c; int len = ( c + 1 ) * ( c + 1 ); _queens = new bool[len]; memset( _queens, 0, len );
_cl = new bool[c]; memset( _cl, 0, c ); _ln = new bool[c]; memset( _ln, 0, c );
point pt; pt.set( rand() % c, rand() % c ); putQueens( pt, c ); displayBoard();
delete [] _queens; delete [] _ln; delete [] _cl;
}
private:
void displayBoard()
{
system( "cls" ); string t = "+---+", q = "| Q |", s = "| |";
COORD c = { 0, 0 }; HANDLE h = GetStdHandle( STD_OUTPUT_HANDLE );
for( int y = 0, cy = 0; y < _count; y++ )
{
int yy = y * _count;
for( int x = 0; x < _count; x++ )
{
SetConsoleCursorPosition( h, c ); cout << t;
c.Y++; SetConsoleCursorPosition( h, c );
if( _queens[x + yy] ) cout << q; else cout << s;
c.Y++; SetConsoleCursorPosition( h, c );
cout << t; c.Y = cy; c.X += 4;
}
cy += 2; c.X = 0; c.Y = cy;
}
}
bool checkD( int x, int y, int a, int b )
{
if( x < 0 || y < 0 || x >= _count || y >= _count ) return true;
if( _queens[x + y * _count] ) return false;
if( checkD( x + a, y + b, a, b ) ) return true;
return false;
}
bool check( int x, int y )
{
if( _ln[y] || _cl[x] ) return false;
if( !checkD( x, y, -1, -1 ) ) return false;
if( !checkD( x, y, 1, -1 ) ) return false;
if( !checkD( x, y, -1, 1 ) ) return false;
if( !checkD( x, y, 1, 1 ) ) return false;
return true;
}
bool putQueens( point pt, int cnt )
{
int it = _count;
while( it )
{
if( !cnt ) return true;
if( check( pt.x, pt.y ) )
{
_queens[pt.x + pt.y * _count] = _cl[pt.x] = _ln[pt.y] = true;
point tmp = pt; if( ++tmp.x >= _count ) tmp.x = 0; if( ++tmp.y >= _count ) tmp.y = 0;
if( putQueens( tmp, cnt - 1 ) ) return true;
_queens[pt.x + pt.y * _count] = _cl[pt.x] = _ln[pt.y] = false;
}
if( ++pt.x >= _count ) pt.x = 0;
it--;
}
return false;
}
int _count;
bool* _queens, *_ln, *_cl;
};
//--------------------------------------------------------------------------------------------------
int main( int argc, char* argv[] )
{
nQueens n; int nq;
while( true )
{
system( "cls" ); cout << "Enter board size bigger than 3 (0 - 3 to QUIT): "; cin >> nq;
if( nq < 4 ) return 0; n.solve( nq ); cout << endl << endl;
system( "pause" );
}
return 0;
}
//--------------------------------------------------------------------------------------------------