HackerRank_GridSearch_C#

//Solution to https://www.hackerrank.com/challenges/the-grid-search/problem
//Anuraag Srivastava

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static void Main(String[] args) {
        int T = Convert.ToInt32(Console.ReadLine());
        for(int i = 0; i < T; i++){
            string[] input = Console.ReadLine().Split();
            int[] values = Array.ConvertAll(input, int.Parse);
            List<string> lines = new List<string>();
            for(int j = 0; j < values[0]; j++){
                lines.Add(Console.ReadLine());
            }
            values = Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
            List<string> pattern = new List<string>();
            for(int j = 0; j < values[0]; j++){
                pattern.Add(Console.ReadLine());
            }
            ProcessInput(lines, pattern, values);
        }
            }
    
    public static bool GetMatch(string a, string b){
        return a == b;
    }
    public static void ProcessInput(List<string> lines, List<string> pattern, int[] values){
         List<int> indexes = new List<int>();
            for(int k = 0; k < lines.Count; k++){
                string str = lines[k];
                indexes.AddRange(AllIndexesOf(str, pattern[0]));
                if(indexes.Count > 0){
                    foreach(int ind in indexes){
                        if(ind != -1){
                            bool isExist = false;
                            int temp = k;
                            foreach(string s in pattern){
                                if(k >= lines.Count){
                                    Console.WriteLine("NO");
                                    return;
                                }
                                isExist = GetMatch(s, lines[temp++].Substring(ind, values[1]));
                                if(!isExist)
                                    break;
                            }
                            if(isExist){
                                Console.WriteLine("YES");
                                return;
                            }
                        }
                    }
                }
                indexes.Clear();
            }
            Console.WriteLine("NO");
    }
    
    public static List<int> AllIndexesOf(string str, string value) {
    if (String.IsNullOrEmpty(value))
            throw new ArgumentException("the string to find may not be empty", "value");
        List<int> indexes = new List<int>();
        int index = 0;
        int temp = 0;
        while (index != -1)
        {
            string t = str.Substring(index);
            temp = t.IndexOf(value);
            if (temp == -1)
                return indexes;
            indexes.Add(temp + index);
            index += temp + 1; 
        }
        return indexes;
}
        
    }