HackerRAnk NCR codesprint - spiral message - submission #3 - score 6.94

SpiralMessage1_submission_3.cs

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

namespace SpiralMessage
{
    class Program
    {
        /*
         * https://www.hackerrank.com/contests/ncr-codesprint/challenges/spiral-message
         * 11:42am start to read problem statement
         * Write a code to work on the sample test case first, we do not need to store
         * result of string, just keep counting. 
         * 3 5 
         * a##ar
         * a#aa#
         * xxwsr
         * 
         * 12:21pm 
         * 4.49/ 20 
         * test cases: 0 - 13
         * pass: 0, 11, 12, 13
         * 
         * 1:07pm 
         * 6.12/ 20 
         * test cases: 0 - 13
         * pass: 
         */
        static void Main(string[] args)
        {
            process();

            // testing the code 
            //testing(); 
            //testing2(); 
        }
        /*
         * test case:
         * 3 5
            a##ar
            a#aa#
            xxwsr
         * 
         * 
         * 
         */
        private static void testing()
        {


            IList<string> input = new List<string>();
            input.Add("a##ar");
            input.Add("a#aa#");
            input.Add("xxwsr");

            Console.WriteLine(calculate(input));
        }

        /*
         * Fail the test 
         */
        private static void testing2()
        {


            IList<string> input = new List<string>();
            input.Add("a");
            input.Add("#");
            input.Add("#");
            input.Add("a");
            input.Add("#");

            Console.WriteLine(calculate(input));
        }

        private static void process()
        {
            int[] arr = ToInt(Console.ReadLine().Split(' '));
            int rows = arr[0], cols = arr[1];

            IList<string> input = new List<string>();
            for (int i = 0; i < rows; i++)
            {
                input.Add(Console.ReadLine().Trim());
            }

            Console.WriteLine(calculate(input));
        }

        /*
         * start: 11:53am
         * exit: 12:15
         * static analysis the code
         */
        private static int calculate(IList<string> data)
        {
            int rows = data.Count;
            int cols = data[0].Length;

            int row = 0;
            int col = 0;
            int count = 0;

            StringBuilder sb = new StringBuilder();

            bool previous = false; // alpahbetic a-z
            int startX = row, endX = rows - 1 - row;
            int startY = col, endY = cols - 1 - col;

            Dictionary<string, int> table = new Dictionary<string, int> (); 

            //while (row < rows && col < cols)
            while (startX <= endX &&
                   startY <= endY &&
                   startX <= (rows - 1) &&
                   startY <= (cols - 1)                    
                )
            {
                // go over 4 direction
                // to right, downward, to left, to up
                // 1. to right                
                for (int j = startY; j <= endY; j++)
                {                    
                    string key = row + "+" + j;
                    bool isIn = table.ContainsKey(key); 
                    bool current = isAlphabetic(data[row][j]);

                    if(!isIn)
                        sb.Append(data[row][j]);

                    if (current && !previous && !isIn)
                    {
                        count++;
                        table.Add(key, 1); 
                    }
                    previous = current;
                }

                // 2. downward
                for (int i = startX + 1; i <= endX; i++)
                {
                    string key = i + "+" + endY;
                    bool isIn = table.ContainsKey(key); 

                    bool current = isAlphabetic(data[i][endY]);

                    if (!isIn)
                        sb.Append(data[i][endY]);

                    if (current && !previous && !isIn)
                    {
                        count++;
                        table.Add(key, 1);
                    }
                    previous = current;
                }

                // 3. to left 
                for (int j = endY - 1; j >= startY; j--)
                {
                    string key = endX + "+" + j;
                    bool isIn = table.ContainsKey(key); 

                    bool current = isAlphabetic(data[endX][j]);

                    if (!isIn)
                        sb.Append(data[endX][j]);

                    if (current && !previous && !isIn)
                    {
                        count++;
                        table.Add(key, 1);
                    }

                    previous = current;
                }

                // 4. to upward
                for (int i = endX - 1; i > startX; i--)
                {
                    string key = i + "+" + startY;
                    bool isIn = table.ContainsKey(key); 

                    bool current = isAlphabetic(data[i][startY]);

                    if (!isIn)
                        sb.Append(data[i][startY]);

                    if (current && !previous && isIn)
                    {
                        count++;
                        table.Add(key, 1);
                    }

                    previous = current;
                }

                row++;
                col++;

                startX = row;
                endX = rows - 1 - row;
                startY = col;
                endY = cols - 1 - col;
            }

            string res = sb.ToString();
            return count;
        }

        private static bool isAlphabetic(char c)
        {
            if ((c - 'a') >= 0 && ('z' - c) >= 0)
                return true;
            else
                return false;
        }

        private static int[] ToInt(string[] arr)
        {
            int len = arr.Length;
            int[] res = new int[len];
            for (int i = 0; i < len; i++)
            {
                res[i] = Convert.ToInt32(arr[i]);
            }

            return res;
        }
    }
}

code review after the contest:

1. The while loop - 115 - 119, but line 118, 119 redundant, part of first two lines.
2. Base case - one row, one column do not work - count twice
3. Add debug code - stringBuilder to tracker the string output - it is helpful, but unfortunately in the contest, Julia did not catch the error - starting point.
4. Missing start time/ end time for submission above function comment, need to track time spent.