java - 求 boolean 矩阵中最大区域的长度

Question

我有一个类(class)，他们计算矩阵中最大的“1”岛，但他的岛概念是“如果两个单元在水平、垂直或对角线上彼此相邻，则称它们是相连的。 “

我需要帮助来删除对角台阶。

class GFG {
    static int ROW, COL, count;

    static boolean isSafe(int[][] M, int row,
                          int col, boolean[][] visited) {
        return ((row >= 0) && (row < ROW) && (col >= 0)
                && (col < COL) && (M[row][col] == 1 &&
                !visited[row][col]));
    }

    static void DFS(int[][] M, int row,
                    int col, boolean[][] visited) {
        int[] rowNbr = {-1, -1, -1, 0, 0, 1, 1, 1};
        int[] colNbr = {-1, 0, 1, -1, 1, -1, 0, 1};

        visited[row][col] = true;

        for (int k = 0; k < 8; k++) {
            if (isSafe(M, row + rowNbr[k], col + colNbr[k], visited)) {
                count++;
                DFS(M, row + rowNbr[k], col + colNbr[k], visited);
            }
        }
    }

    static int largestRegion(int[][] M) {
        boolean[][] visited = new boolean[ROW][COL];
        int result = 0;
        for (int i = 0; i < ROW; i++) {
            for (int j = 0; j < COL; j++) {
                if (M[i][j] == 1 && !visited[i][j]) {
                    DFS(M, i, j, visited);
                    result = Math.max(result, count);
                }
            }
        }
        return result;
    }

    public static void main(String args[]) {
        int M[][] = {{0, 0, 1, 1},
                    {1, 0, 1, 1},
                    {0, 1, 0, 0},
                    {0, 0, 0, 0}};
        ROW = 4;
        COL = 4;
        System.out.println(largestRegion(M));
    }
}

打印的响应是 6，但我需要他返回 4 我现在已经尝试了所有方法，但无法解决。算法原帖:https://www.geeksforgeeks.org/find-length-largest-region-boolean-matrix/

Answer 1

只需将邻居数组的坐标更改为4即可。

int rowNbr[] = { -1, 0, 0, 1}; 
int colNbr[] = { 0, -1, 1,  0};

迭代四次

 for (int k = 0; k < 4; ++k) 

The updated code: