HDU 1312 Red and Black "Deep Search"

Red and Black

Time limit:2000/1000 MS (java/others) Memory limit:65536/32768 K (java/others)
Total submission (s): 11531 Accepted Submission (s): 7177

Problem Description

There is a rectangular and covered with square tiles. Each tile is colored either red or black. A man was standing on a black tile. From a tiles, he can move to one of the four adjacent tiles. But he can ' t move on red tiles, and 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 the positive integers W and H; W and H is the numbers of tiles in the X-and y-directions, respectively. W and H is not more than 20.

There is H more lines in the data set, and each of the 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

6 9....#......#..............................#@...#.#. #.11 9.#..........#.#######. #.#.....#.. #.#.###.#.. #.#[email protected]#.#. #.#####.#.. #.......#.. #########............ 11 6..#. #.. #....#.. #.. #....#.. #.. ###.. #.. #.. #@...#.. #.. #....#.. #.. #.. 7 7..#.#....#.#. ###.###[email protected]###.###. #.#....#.#.. 0 0

Sample Output

4559613

Source

Asia 2004, Ehime (Japan), Japan Domestic

#include <stdio.h> #include <string.h>int n,m,cnt;char map[30][30];int to[4][2] = {{1,0},{0,1},{-1,0},{0,- 1}};void DFS (int i,int j) {int k,x,y;     cnt++;    MAP[I][J] = ' # ';    for (k = 0; k<4; k++)    {        x = i + to[k][0];        y = j + to[k][1];        if (x<n && y<m && x>=0 && y>=0 && map[x][y] = = '. ') Control x, y do not let it cross the             dfs (x, y);    }} int main () {    int i,j,fi,fj;    while (scanf ("%d%d%", &m,&n))//horizontal is n, longitudinal is m     {    if (m==0&&n==0) break;        for (i = 0; i<n; i++)        {            for (j = 0; j<m; j + +)            {                scanf ("%c", &map[i][j]);                if (map[i][j] = = ' @ ')//Find the location of the first person                 {                    fi = i;                    FJ = j;                }            }            GetChar ();        }        CNT = 0;        DFS (FI,FJ);        printf ("%d\n", CNT);    }    return 0;}

HDU 1312 Red and Black "Deep Search"