HDOJ1312 Red and Black

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1312

//DFS
#include<iostream>
int count,m,n;
int dir[4][2]={-1,0,1,0,0,-1,0,1};
char map[21][21];
void DFS(int i,int j)
{
    if(i<=0||i>m||j<=0||j>n)
        return;
    for(int k=0;k<4;++k)
        if(i+dir[k][0]>0&&i+dir[k][0]<=m&&j+dir[k][1]>0&&j+dir[k][1]<=n)
            if(map[i+dir[k][0]][j+dir[k][1]]=='.')
            {
                ++count;
                map[i+dir[k][0]][j+dir[k][1]]='#';
                DFS(i+dir[k][0],j+dir[k][1]);
            }
}
int main()
{
    using namespace std;
    int i,j,stx,sty;
    while(cin>>n>>m&&(n||m))
    {
        count=1;
        for(i=1;i<=m;++i)
            for(j=1;j<=n;++j)
            {
                cin>>map[i][j];
                if(map[i][j]=='@')
                {
                    stx=i;
                    sty=j;
                    map[i][j]='#';
                }
            }
        DFS(stx,sty);
        cout<<count<<endl;
    }
    return 0;
}

#include <iostream> 
using namespace std;
//宏定义增强代码适应能力和可读性
#define MAX 22 
char rect[MAX][MAX]; 

int walkFrom(int currentRow, int currentCol); //返回从某点走过的格子数，减少全局量的使用
void main()
{
    int col, row;
    while(cin >> col >> row, col!=0 && row != 0)
    { 
        int i, j, startRow, startCol;
        for(i = 0; i < MAX; i++)//intialize--方块四周加白色块，去掉边界判断，
            for(j=0; j<MAX; j++)
                rect[i][j]='#'; 
        for(i=1;i<=row;i++)
            for(j=1;j<=col;j++)
            {
                cin >> rect[i][j];
                if(rect[i][j] == '@')
                {
                    startRow = i;
                    startCol = j; 
                    rect[i][j]='.';
                }
            }
        cout << walkFrom(startRow,startCol) << endl;
    }
} 
int walkFrom(int currentRow, int currentCol)
{ 
      if(rect[currentRow][currentCol] == '#')
              return 0; 
      else
          rect[currentRow][currentCol] = '#'; 
      return  
         1+walkFrom(currentRow+1,currentCol)+walkFrom(currentRow-1,currentCol)
         +walkFrom(currentRow,currentCol+1)+walkFrom(currentRow,currentCol-1); 
}