题解 | 数水坑

#include <stdio.h>

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

    char ch[105][105];
    for (int i = 0; i < n; i++)
        scanf("%s", ch[i]);

    int dx[8] = {-1, -1, -1,  0, 0,  1, 1, 1};
    int dy[8] = {-1,  0,  1, -1, 1, -1, 0, 1};
    int visited[105][105] = { 0 };
    long long sum = 0;

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (ch[i][j] == 'W' && !visited[i][j]) {
                visited[i][j] = 1;
                sum++;

                int front = 0, rear = 0;
                int qx[105 * 105], qy[105 * 105];
                qx[rear] = i, qy[rear] = j;
                rear++;

                while (front < rear) {
                    int x = qx[front];
                    int y = qy[front];
                    front++;

                    for (int k = 0; k < 8; k++) {
                        int cur_x = x + dx[k];
                        int cur_y = y + dy[k];

                        if (cur_x < 0 || cur_x >= n || cur_y < 0 || cur_y >= m)  continue;
                        if (visited[cur_x][cur_y])   continue;
                        if (ch[cur_x][cur_y] != 'W') continue;

                        visited[cur_x][cur_y] = 1;
                        qx[rear] = cur_x;
                        qy[rear] = cur_y;
                        rear++;
                    }
                }
            }
        }
    }
    printf("%lld\n", sum);
    return 0;
}