Solution.java

public class Solution
{    //Brute force solution    public int longestLine(int[][] M)    {        int len = 0;        if (M == null || M
    // .length == 0 || M[0].length == 0)        {            return len;        }        int rows = M.length;
// int cols = M[0].length;        for (int i = 0; i < rows; i++)        {            for (int j = 0; j < cols; j++)
// {                if (M[i][j] != 0)                {                    len = Math.max(dfs(M, i, j, rows, cols),
// len);                }            }        }        return len;    }    private int dfs(int[][] matrix, int
// rowIdx, int colIdx, int rows, int cols)    {        int len = 0;        //vertical        int i = rowIdx;
// int curr = 0;        while (i < rows && matrix[i][colIdx] == 1)        {            i++;            curr++;
// }        len = Math.max(curr, len);        //Horizontal        int j = colIdx;        curr = 0;        while (j <
// cols && matrix[rowIdx][j] == 1)        {            j++;            curr++;        }        len = Math.max(curr,
// len);        //diagonal        i = rowIdx;        j = colIdx;        curr = 0;        while (i < rows && j < cols
// && matrix[i][j] == 1)        {            curr++;            i++;            j++;        }        len = Math.max
// (curr, len);        //anti diagonal        i = rowIdx;        j = colIdx;        curr = 0;        while (j >= 0 &&
// i < rows && matrix[i][j] == 1)        {            curr++;            i++;            j--;        }        len =
// Math.max(curr, len);        return len;    }}