八皇后问题JAVA程序

八皇后问题JAVA程序

public class Queen

{

static int QueenMax = 8;

static int times = 0;

static int chess[] = new int[QueenMax];

public static void placequeen(int num)

{

int i=0;

boolean save[] = new boolean[QueenMax];

for(;i

save[i]=true;

i=0;

while (i

{

save[chess[i]]=false;

int k=num-i;

if ( (chess[i]+k >= 0) && (chess[i]+k < QueenMax) ) save[chess[i]+k]=false;

if ( (chess[i]-k >= 0) && (chess[i]-k < QueenMax) ) save[chess[i]-k]=false;

i++;

}

for(i=0;i

{

if (save[i]==false)

continue;

if (num

{

chess[num]=i;

placequeen(num+1);

}

else

{

chess[num]=i;

times++;

System.out.println("这是第"+times+"种解法如下:");

for (i=0;i

{

String row="";

if (chess[i]==0);

else

for(int j=0;j

row+="* ";

row+="Q ";

int j = chess[i];

while(j

{

row+="* ";j++;

}

System.out.println(row);

}

}

}

}

public static void main(String args[])

{

long start = System.currentTimeMillis();

for (int i=0;i

chess[i]=-1;

placequeen(0);

System.out.println("八皇后问题共有"+times+"种答案 \n");

long end = System.currentTimeMillis();

System.out.println("程序运行时间："+(end -start)+"ms");

}

}