Challenge Program 2.1.4 Exhaustion Search >> Depth First search exercises POJ1979 black and red

http://poj.org/problem?id=1979

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)
The end of the input is indicated by a line consisting of the zeros.

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).Ideas:(⊙v⊙) Well, the same as the example, from the @, search all the places you can go to, change it to a value (@ or what is true), and finally go through the map.

1#include <stdio.h>2 Charch[ -][ -];3 voidSolveintHintW);4 voidFind1 (intHintW);5 voidDfsintXintYintHintW);6 intMain ()7 {8     inth,w,i;9      while(SCANF ("%d%d", &w,&h)!=eof&&h!=0&&w!=0)Ten     { One GetChar (); A       for(i=0; i) - gets (Ch[i]); - Find1 (h,w); the solve (h,w); -     } -     return 0; - } +  - voidSolveintHintW) + { A     intA=0; at      for(intI=0; i) -          for(intk=0; k<w;k++) -             if(ch[i][k]=='@') -a++; -printf"%d\n", a); - } in  - voidFind1 (intHintW) to { +      for(intI=0; i) -          for(intk=0; k<w;k++) the             if(ch[i][k]=='@') *                 { $ DFS (I,K,H,W);Panax Notoginseng                     return; -                 } the } +  A voidDfsintXintYintHintW) the { +     intX1,y1,nx,ny; -ch[x][y]='@'; $      for(x1=-1; x1<=1; x1++) $     { -nx=x+X1; -             if(nx>=0&&nx'#'&&ch[nx][y]!='@') the DFS (NX,Y,H,W); -     }Wuyi      for(y1=-1; y1<=1; y1++) the     { -ny=y+Y1; Wu             if(ny>=0&&ny<w&&ch[x][ny]!='#'&&ch[x][ny]!='@') - DFS (X,NY,H,W); About     } $     return; -}

Challenge Program 2.1.4 Exhaustion Search >> Depth First search exercises POJ1979 black and red