POJ2386-Lake Counting

#include <cstdio>

const int MAXN = 100;
char field[MAXN+2][MAXN+2];
int n, m;

void Dfs(int x, int y)
{
if (field[x][y] == 'W') {
field[x][y] = '.';

for (int dx = -1; dx <= 1; dx++) {
for (int dy = -1; dy <= 1; dy++) {
int nx = x + dx;
int ny = y + dy;
if (0 <= nx && nx < n && 0 <= ny && ny < m && field[nx][ny] == 'W') {
Dfs(nx, ny);
}
}
}
}
}

int main()
{
scanf("%d%d", &n, &m);

int i, j;
for (i = 0; i < n; i++) {
scanf("%s", field[i]);
}

int cnt = 0;
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
if (field[i][j] == 'W') {
Dfs(i, j);
cnt++;
}
}
}

printf("%d\n", cnt);

return 0;
}