简单搜索——杭电1312Red and Black

Red and Black

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 20144    Accepted Submission(s): 12243

Problem Description

There is a rectangular room, covered with square tiles. Each tile is colored either red or black. A man is standing on a black tile. From a tile, he can move to one of four adjacent tiles. But he can't move on red tiles, he can move only on black tiles.

Write a program to count the number of black tiles which he can reach by repeating the moves described above.

 

Input

The input consists of multiple data sets. A data set starts with a line containing two positive integers W and H; W and H are the numbers of tiles in the x- and y- directions, respectively. W and H are not more than 20.

There are H more lines in the data set, each of which includes W characters. Each character represents the color of a tile as follows.

'.' - a black tile
'#' - a red tile
'@' - a man on a black tile(appears exactly once in a data set)

 

Output

For each data set, your program should output a line which contains the number of tiles he can reach from the initial tile (including itself).

 

Sample Input

Sample Output

45

59

6

13

代码实现

#include<stdio.h>
char map[22][22];
int que[1000][2];
int sx[4]={0,0,-1,1};
int sy[4]={1,-1,0,0};
int h,w;
int dfs(int x,int y)
{
    int t,xx,yy,i,j,s=1;
    i=j=0;
    que[i][0]=x;
    que[i][1]=y;
    i++;
    map[x][y]='#';
    while(j<i)
    {
        xx=que[j][0];
        yy=que[j][1];
        for(t=0;t<4;t++)
        {
            x=xx+sx[t];
            y=yy+sy[t];
            if(x>=1&&x<=h&&y>=1&&y<=w&&map[x][y]!='#')
            {
                que[i][0]=x;
                que[i][1]=y;
                i++;
                map[x][y]='#';
                s++;
            }
        }
        j++;
    }
    return s;
}

int main()
{
    int i,j,x,y;
    while(scanf("%d%d",&w,&h)!=EOF)
    {
        if(h==0&&w==0)break;
        for(i=1;i<=h;i++)
        {
            getchar();
            for(j=1;j<=w;j++)
            {
                scanf("%c",&map[i][j]);
                if(map[i][j]=='@')
                {
                    x=i;
                    y=j;
                }
            }
        }
        printf("%d
",dfs(x,y));
    }
    return 0;
}