题解 | 数水坑

#include<bits/stdc++.h>
using namespace std;
const int N = 101;
int n, m;
char a[N][N];
bool vis[N][N] = {false};
int dx[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int dy[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
void dfs(int x, int y) {
    vis[x][y] = true;
    for (int i = 0; i < 8; i++) {
        int nx = x + dx[i], ny = y + dy[i];
        if (1 <= nx && nx <= n && 1 <= ny && ny <= m && !vis[nx][ny] &&
                a[nx][ny] == 'W') {
            dfs(nx, ny);
        }
    }
}
int main() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];
        }
    }
    int ans = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (a[i][j] == 'W' && !vis[i][j]) {
                ans++;
                dfs(i, j);
            }
        }
    }
    cout << ans << endl;
    return 0;
}