HDU 1312 Red and Black

Red and Black

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 22320    Accepted Submission(s): 13577

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

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

 

Sample Output

4559613
深搜代码
#include<iostream>#include<string.h>#include<stdio.h>using namespace std;int maxn=10010;char a[22][22];int f[4][2]={{-1,0},{1,0},{0,-1},{0,1}};int l=1,s,aa,b,a1,b1;int Judge(int x1,int y1){    if(x1<0||x1>=aa||y1<0||y1>=b)return 0;    if(a[x1][y1]!='.')return 0;    return 1;}void dfs(int x,int y){    for(int k=0;k<4;k++){        int x1,y1;        x1=x+f[k][0];        y1=y+f[k][1];        if(Judge(x1,y1)){            a[x1][y1]='#';            l++;            dfs(x1,y1);            l--;            s++;        }    }}int main(){    while(scanf("%d %d",&b,&aa)&&(b||aa)){    s=1;    for(int i=0;i<aa;i++){        for(int j=0;j<b;j++){            cin>>a[i][j];            if(a[i][j]=='@'){                a1=i;b1=j;            }        }    }    dfs(a1,b1);    cout<<s<<endl;    }}