HDU 1312 Red and Black (DFS)
Red and Black
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 9795 Accepted Submission(s): 6103
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.
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)
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
45
59
6
13
Source
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1 #include<cstdio> 2 #include<iostream> 3 #include<cstring> 4 #include<stdlib.h> 5 #include<algorithm> 6 using namespace std; 7 const int MAXN=100; 8 int dir[4][2]={{0,1},{1,0},{0,-1},{-1,0}}; 9 char map[MAXN][MAXN],s[MAXN]; 10 int vis[MAXN][MAXN]; 11 int ans,n,m; 12 void DFS(int x,int y) 13 { 14 vis[x][y]=1; 15 ans++; 16 for(int i=0;i<4;i++) 17 { 18 int xx=x+dir[i][0]; 19 int yy=y+dir[i][1]; 20 if(0<=xx&&xx<n&&0<=yy&&yy<m&&!vis[xx][yy]&&map[xx][yy]!='#') 21 DFS(xx,yy); 22 } 23 } 24 int main() 25 { 26 //freopen("in.txt","r",stdin); 27 int x,y; 28 while(scanf("%d %d%*c",&m,&n)&&(n||m)) 29 { 30 for(int i=0;i<n;i++) 31 { 32 for(int j=0;j<m;j++) 33 { 34 scanf("%c",&map[i][j]); 35 if(map[i][j]=='@') 36 { 37 x=i; 38 y=j; 39 } 40 } 41 getchar(); 42 } 43 memset(vis,0,sizeof(vis)); 44 ans=0; 45 DFS(x,y); 46 printf("%d\n",ans); 47 } 48 return 0; 49 }