K index - algorithm - fix 2 bugs - one is to continue to do DFS, conditional checking; second is DFS calls return handling

kIndex2.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace kIndex
{
    class Program
    {
        static void Main(string[] args)
        {
            int k = Convert.ToInt16(Console.ReadLine());

            int[][] arr = new int[k][];

            for (int i = 0; i < k; i++)
                arr[i] = new int[k];

            for (int i = 0; i < k; i++)
            {
                string s = Console.ReadLine();
                string[] aA = s.Split(' ');
                if (aA.Length != k)
                    return;
                for (int j = 0; j < k; j++)
                    arr[i][j] = Convert.ToInt16(aA[j].Trim());
            }

            int kIndex = Convert.ToInt16(Console.ReadLine());
            if (kIndexFunc(arr, kIndex))
            {
                Console.WriteLine("YES");
            }
            else
                Console.WriteLine("NO");
        }

        public static bool kIndexFunc(int[][] arr, int kIndex)
        {
            if (arr == null) return false;

            int m = arr.Length;
            int n = arr[0].Length;
            if (m != n)
                return false;

            for (int i = 0; i < m; i++)
                for (int j = 0; j < m; j++)
                {
                    int search = arr[i][j];
                    if (searchInKIndex(arr, i, j, kIndex, search, m))
                        return true;
                }
            return false;
        }

        private static bool searchInKIndex(int[][] arr, int row, int col, int kIndex, int search, int MaxRow)
        {
            bool[][] searchedA = new bool[MaxRow][];

            for (int i = 0; i < MaxRow; i++)
                searchedA[i] = new bool[MaxRow];

            for (int i = 0; i < MaxRow; i++)
                for (int j = 0; j < MaxRow; j++)
                    searchedA[i][j] = false;

            // up, down, left, right
            return DFS(arr, row, col, row, col, kIndex, search, MaxRow, searchedA);

        }

        private static bool DFS(int[][] arr, int oriX, int oriY, int row, int col, int kIndex, int search, int MaxRow, bool[][] searchedA)
        {
            if (!isValid(row, MaxRow) || !isValid(col, MaxRow) || kIndex < 0)
                return false;
            
            if (Math.Abs(oriX - row) + Math.Abs(oriY - col) > 0 &&  !searchedA[row][col] )
            {
                if (arr[oriX][oriY] == arr[row][col])
                    return true;                              
            }
            
            searchedA[row][col] = true;  // bug001 - check condition is wrong 

            if (DFS(arr, oriX, oriY, row - 1, col, kIndex - 1, search, MaxRow, searchedA) ||
            DFS(arr, oriX, oriY, row + 1, col, kIndex - 1, search, MaxRow, searchedA) ||
            DFS(arr, oriX, oriY, row, col + 1, kIndex - 1, search, MaxRow, searchedA) ||
            DFS(arr, oriX, oriY, row, col - 1, kIndex - 1, search, MaxRow, searchedA))
                return true; // any of conditions are ok, then, return true

            return false;
        }

        private static bool isValid(int row, int MaxRow)
        {
            if (row >= 0 && row < MaxRow)
                return true;
            else
                return false;
        }

    }
}