ZOJ 1002 Fire Net

AC代码:

#include<iostream>
using namespace std;
int n;
int ans;
char map[10][10];
bool check(int x,int y);
void dfs(int point,int sum);
int main()
{
    while(scanf("%d",&n)!= EOF)
    {
        if(n==0)
            break;
        getchar();
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<n;j++)
                scanf("%c",&map[i][j]);
            getchar();
        }
        ans = 0;
        dfs(0,0);
        printf("%d\n",ans);
    }
    return 0;
}
bool check(int x,int y)
{
    bool flag = true;
    for(int i=x;i>=0;i--)
    {
        if(map[i][y]=='X')
            break;
        else if(map[i][y]=='b')
        {
            flag = false;
            break;
        }
    }
    for(int i=y;i>=0;i--)
    {
        if(map[x][i]=='X')
            break;
        else if(map[x][i]=='b')
        {
            flag = false;
            break;
        }
    }
    return flag;
}
void dfs(int point,int sum)
{
    if(point == n*n)
    {
        if(sum>ans)
            ans = sum;
        return;
    }
    int x = point/n;
    int y = point%n;
    if(map[x][y]=='.'&&check(x,y))
    {
        map[x][y]='b';
        dfs(point+1,sum+1);
        map[x][y]='.';
    }
        dfs(point+1,sum);
}