zoj 2412 Farm Irrigation [ dfs ]

#include<stdio.h>
#include<string.h>

#define I (i*3)
#define J (j*3)
char str[51][51];
int map[159][159];
int n, m;
int dir[4][2] =
{
{0, 1}, {0, -1}, {-1, 0}, {1, 0}
};

void dfs(int i, int j)
{
map[i][j] = 0;
for(int k = 0; k < 4; k++) {
int x = i + dir[k][0];
int y = j + dir[k][1];
if(x >= 0 && x < 3*n && y >= 0 && y < 3*m && map[x][y]) {
dfs(x, y);
}
}
}

int main()
{
while(scanf("%d %d%*c", &n, &m) != EOF) {
if(n < 0 || m < 0) break;
memset(map, 0, sizeof(map));
for(int i = 0; i < n; i++) {
for(int j = 0; j < m; j++) {
scanf("%c", &str[i][j]);
if( str[i][j] == 'A' ) {
map[I][J+1] = map[I+1][J] = map[I+1][J+1] = 1;
}
if( str[i][j] == 'B' ) {
map[I+1][J+1] = map[I+1][J+2] = map[I][J+1] = 1;
}
if( str[i][j] == 'C' ) {
map[I+2][J+1] = map[I+1][J] = map[I+1][J+1] = 1;
}
if( str[i][j] == 'D' ) {
map[I+2][J+1] = map[I+1][J+2] = map[I+1][J+1] = 1;
}
if( str[i][j] == 'E' ) {
map[I][J+1] = map[I+2][J+1] = map[I+1][J+1] = 1;
}
if( str[i][j] == 'F' ) {
map[I+1][J+2] = map[I+1][J] = map[I+1][J+1] = 1;
}
if( str[i][j] == 'G' ) {
map[I+1][J+2] = map[I+1][J] = map[I+1][J+1] = map[I][J+1] = 1;
}
if( str[i][j] == 'H' ) {
map[I][J+1] = map[I+2][J+1] = map[I+1][J+1] = map[I+1][J] = 1;
}
if( str[i][j] == 'I' ) {
map[I+1][J+2] = map[I+1][J] = map[I+1][J+1] = map[I+2][J+1] = 1;
}
if( str[i][j] == 'J' ) {
map[I][J+1] = map[I+2][J+1] = map[I+1][J+1] = map[I+1][J+2] = 1;
}
if( str[i][j] == 'K' ) {
map[I][J+1] = map[I+2][J+1] = map[I+1][J+1] = map[I+1][J+2] = map[I+1][J] = 1;
}
}
scanf("%*c");
}
/**************************
for(int i = 0; i < 3*n; i++) {
for(int j = 0; j < 3*m; j++) {
printf("%d ", map[i][j]);
}
printf("\n");
}
**************************/

int ans = 0;
for(int i = 0; i < 3*n; i++) {
for(int j = 0; j < 3*m; j++) {
if(map[i][j]) {
dfs(i, j);
ans++;
}
}
}
printf("%d\n", ans);
}
return 0;
}