hdoj-1312-Red and Black

Red and Black

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)

Total Submission(s): 12433 Accepted Submission(s): 7726



[align=left]Problem Description[/align]
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.

[align=left]Input[/align]
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)

[align=left]Output[/align]
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).

[align=left]Sample Input[/align]

6 9
....#.
.....#
......
......
......
......
......
#@...#
.#..#.
11 9
.#.........
.#.#######.
.#.#.....#.
.#.#.###.#.
.#.#..@#.#.
.#.#####.#.
.#.......#.
.#########.
...........
11 6
..#..#..#..
..#..#..#..
..#..#..###
..#..#..#@.
..#..#..#..
..#..#..#..
7 7
..#.#..
..#.#..
###.###
...@...
###.###
..#.#..
..#.#..
0 0

[align=left]Sample Output[/align]

45
59
6
13

[align=left]Source[/align]
Asia 2004, Ehime (Japan), Japan Domestic

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#include<stdio.h>
#include<string.h>
char map[22][22];
int  dd[22][22];
int  n,m;
void DP(int i,int j,int &res){
if(i<=0||i>n||j<0||j>=m) return ;
if(map[i][j]=='#') return;
if(dd[i][j]==0&&(map[i][j]=='.'||map[i][j]=='@')) {
dd[i][j]=1;
res++;
DP(i-1,j,res);DP(i+1,j,res);
DP(i,j-1,res);DP(i,j+1,res);
}
}
int main(){
while(scanf("%d %d",&m,&n),n||m){
memset(map,0,sizeof(map));
memset(dd,0,sizeof(dd));
int i,j,res,num=0;int tx,ty;

for(i=1;i<=n;++i){
scanf("%s",map[i]);
}
for(i=1;i<=n;++i){
for(j=0;j<m;++j)
if(map[i][j]=='@')
tx=i,ty=j;
}
//printf("%d====%d\n",tx,ty);;
res=0;
DP(tx,ty,res);
printf("%d\n",res);
}
return 0;
}