zoj 1002 dfs

#include<algorithm>
#include<iostream>
#include<cstdio>
#include<stack>
#include<cstdlib>

using namespace std;
char map[5][5]; 
int num, n;
bool find(int x,int y)//判断当前位置能不能放 
{
     int i, j;
    for(i=0; i<y; i++)   //y 坐标的判断
    if(map[x][i]=='X')
    break;
    else if(map[x][i]=='K')
    return false; 
    for(j=0; j<x; j++)  //x坐标的判断 
    if(map[j][y]=='X')
    break;
    else if(map[j][y]=='K')
    return false;
    
    return true;
} 
int dfs(int x, int count)
{
    int i,j;
    if(num<count) num = count;
    for(i=x; i<n; i++)
    for(j=0; j<n; j++)
    if(map[i][j]!='K'&& map[i][j]!='X' && find(i,j)) //如果当前位置可放的话就继续搜素
    {
    map[i][j] = 'K';
    count++;
    dfs(i,count);
    count = 0;     //递归后应该将改变的量再次变过来
    map[i][j]='.';
    } 
    
}
int main()
{
    while(scanf("%d",&n)&&n)
     {
      getchar();
      for(int i=0; i<n; i++)
      gets(map[i]);
      num = 0;
      dfs(0, 0);
      printf("%d\n",num);
     }
   system("pause");
   return 0;
}