题解

补充个dfs做法，Acwing过，PAT段错误

C++ 代码

#include <iostream>
#include <cstring>

using namespace std;

const int M = 1300, N = 130, L = 65;

int n, m, l, t;
bool a[L][M][N];
const int d[][3] = {
    {1, 0, 0},
    {-1, 0, 0},
    {0, 1, 0},
    {0, -1, 0},
    {0, 0, 1},
    {0, 0, -1},
};

int dfs(int i, int j, int k)
{
    // cout << i << " " << j << " " << k << ":" << endl;
    int res = 0;
    a[i][j][k] = false;
    for (int p = 0; p < 6; p ++ )
    {
        // cout << d[l][0] << " " << d[l][1] << " " << d[l][2] << endl;
        int z = d[p][0] + i;
        int y = d[p][1] + j;
        int x = d[p][2] + k;

        if (x >= 0 && x < n && y >= 0 && y < m && z >= 0 && z < l && a[z][y][x]) res += dfs(z, y, x);
    }
    return res + 1;
}

int main()
{
    cin >> m >> n >> l >> t;

    for (int i = 0; i < l; i ++ )
    {
        for (int j = 0; j < m; j ++ )
        {
            for (int k = 0; k < n; k ++ )
            {
                cin >> a[i][j][k];
            }
        }
    }

    int res = 0;
    for (int i = 0; i < l; i ++ )
    {
        for (int j = 0; j < m; j ++ )
        {
            for (int k = 0; k < n; k ++ )
            {
                if (a[i][j][k]) 
                {
                    int cnt = dfs(i, j, k);
                    if (cnt >= t) res += cnt;
                    // cout << cnt << endl;
                }
            }
        }
    }
    cout << res << endl;

    return 0;
}