题解

#include<iostream>
#include<queue>
using namespace std;
int ans=0;
bool vis[405][405];
char dis[405][405];
int n,m;
struct Node {
	int x,y;
};
int dx[8]= {-1,-1,-1,0,1,1,1,0};
int dy[8]= {-1,0,1,1,1,0,-1,-1};
bool check(int x,int y) {
	return x >= 1 && x <= n && y >= 1 && y <= m && vis[x][y] == 0 && dis[x][y] == 'W';
}

void bfs(int x,int y) {
	queue <Node > q;
	q.push({x,y});
	vis[x][y] = true;
    dis[x][y] = '.';
	while (!q.empty()) {
		Node t = q.front();
		q.pop();
		for (int i = 0; i < 8; i ++) {
			int xx = t.x + dx[i];
			int yy = t.y + dy[i];
			if (check(xx,yy)) {
				q.push({xx,yy});
				vis[xx][yy] = true;
				dis[xx][yy] = dis[t.x][t.y] + 1;
			}
		}
	}
}

int main() {

	cin >> n >> m;
	for(int i = 1; i <= n; i ++) {
		for(int j = 1; j <= m; j ++) {
			cin >> dis[i][j];
		}
	}
    
    for(int i = 1; i <= n; i ++) {
		for(int j = 1; j <= m; j ++) {
			if (dis[i][j] == 'W' && vis[i][j] == 0) {
                bfs(i,j);
                ans ++ ;
            }
		}
	}
    
	
    cout << ans;

	return 0;
}