深搜

#include <bits/stdc++.h>
using namespace std;

int dir[8][4] = { {0, 1}, {1, 0}, {-1, 0}, {0, -1} , {-1, -1}, {1, 1}, {-1, 1}, {1, -1}};//注意是八个方位，这里要改一下
int n, m, ans;
char mp[4500][4500];
bool vis[4500][4500];

bool check(long long x, long long y) {
    return x >= 1 && x <= n && y >= 1 && y <= m && mp[x][y] == 'W' && !vis[x][y];
}

void dfs(long long x, long long y) {
    vis[x][y] = true; //把每个经过的水洼都标记
    for (int i = 0; i < 8; i ++) {//方向数组改了这里的循环也要改一下
        int tn = x + dir[i][0];
        int ty = y + dir[i][1];
        if (check(tn, ty)) {
            vis[tn][ty] = true;
            dfs(tn, ty);
        }
    }
}

// 其他就是最简单的深搜模板了
int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i ++) {
        for (int j = 1; j <= m; j ++) {
            cin >> mp[i][j];
        }
    }
    for (int i = 1; i <= n; i ++) {
        for (int j = 1; j <= m; j ++) {
            if (mp[i][j] == 'W' && !vis[i][j]) {//判断是否是水洼，
                dfs(i, j);
                ans ++;
            }
        }
    }
    cout << ans;
    return 0;
}