ZOJ 2412 Farm Irrigation

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int n,m;
struct node
{
int is;
int up,down,left,right;
}e,t,mat[51][51];
struct node change(char c) //把字符转换为各种地图的情况
{
struct node t;
t.left=t.right=t.up=t.down=0;
if( c == 'A' ) {t.left=t.up=1;return t;}
if( c == 'B' ) {t.right=t.up=1;return t;}
if( c == 'C' ) {t.left=t.down=1;return t;}
if( c == 'D' ) {t.right=t.down=1;return t;}
if( c == 'E' ) {t.down=t.up=1;return t;}
if( c == 'F' ) {t.left=t.right=1;return t;}
if( c == 'G' ) {t.left=t.up=t.right=1;return t;}
if( c == 'H' ) {t.left=t.up=t.down=1;return t;}
if( c == 'I' ) {t.left=t.down=t.right=1;return t;}
if( c == 'J' ) {t.right=t.down=t.up=1;return t;}
if( c == 'K' ) {t.left=t.right=t.up=t.down=1;return t;}
return t;
}
void dfs( int x,int y )  //dfs过程，就是把连接着的周围农田标记成已经得到灌溉
{
if(  mat[x][y].up && !mat[x-1][y].is && mat[x-1][y].down )
mat[x-1][y].is=1,dfs(x-1,y);

if(  mat[x][y].down && !mat[x+1][y].is && mat[x+1][y].up )
mat[x+1][y].is=1,dfs(x+1,y);

if( mat[x][y].left && !mat[x][y-1].is && mat[x][y-1].right )
mat[x][y-1].is=1,dfs(x,y-1);

if( mat[x][y].right &&!mat[x][y+1].is &&  mat[x][y+1].left )
mat[x][y+1].is=1,dfs(x,y+1);
}
int main(void)
{
int i,j,count;
char c;
while( scanf("%d%d",&n,&m) != EOF )
{
getchar();
if( n < 0 && m <0  ) break;

for( i = 1; i <= n; i++ ){
for( j = 1; j <= m; j++ )
{
c = getchar();
mat[i][j] = change(c);
mat[i][j].is = 0;
}
getchar();
}
for( i = 1; i <= n; i++ ) mat[i][1].left = mat[i][m].right = 0;
for( i = 1; i <= m; i++ ) mat[1][i].up = mat
[i].down = 0;
count = 0;
for( i = 1; i <= n; i++ )
for( j = 1; j <= m; j++ )
if( mat[i][j].is == 0 )
mat[i][j].is = 1,dfs(i,j),count++;
printf("%d/n",count);
}
return 0;
}