基础练习 2n皇后问题

解答代码

#include<iostream>#include<string>#include<cstdio>#include<cmath>#define maxSize 128int blackFlag[maxSize];int whiteFlag[maxSize];int chessBoard[maxSize][maxSize];int counter=0;int n;using namespace std;int blackQueend(int pos);int whiteQueen(int pos);int blackQueen(int pos){	int i,j;	for(i=0;i<pos-1;i++)	{		if(blackFlag[i]==blackFlag[pos-1] || fabs(pos-1-i)==fabs(blackFlag[i]-blackFlag[pos-1]))			return 0;	}	if(pos==n)	{		counter++;		return 0;	}	for(j=0;j<n;j++)	{		if(j!=whiteFlag[pos] && chessBoard[pos][j]==1)		{			blackFlag[pos]=j;			blackQueen(pos+1);		}	}}int whiteQueen(int pos){	int i,j;	for(i=0;i<pos-1;i++)	{		if(whiteFlag[i]==whiteFlag[pos-1] || fabs(pos-1-i)==fabs(whiteFlag[i]-whiteFlag[pos-1]))			return 0;	}	if(pos==n)	{		blackQueen(0);		return 0;	}	for(j=0;j<n;j++)	{		if(chessBoard[pos][j]==1)		{			whiteFlag[pos]=j;			whiteQueen(pos+1);		}	}}int main(){	//freopen("input2.txt","r",stdin);	int i,j;		cin>>n;	//cout<<n<<endl;	for(i=0;i<n;i++)		for(j=0;j<n;j++)			cin>>chessBoard[i][j];	whiteQueen(0);	cout<<counter<<endl;	return 0;}