C#•12mo ago

Advent of Code Day 1

I'm not sure why my code isn't accepted even though I'm sure it works:

private int Sum() 
{
   int Overall = 0;

   Console.WriteLine("Enter the calibration document. Enter an empty line to finish.");

   string line;
   while ((line = Console.ReadLine()) != "")
   {
       int firstDigit = 0;
       int lastDigit = 0;

       // Find the first digit
       for (int i = 0; i < line.Length; i++)
       {
           if (Char.IsDigit(line[i]))
           {
               firstDigit = Int32.Parse(line[i].ToString());
               break;
           }
       }

       // Find the last digit
       for (int i = line.Length - 1; i >= 0; i--)
       {
           if (Char.IsDigit(line[i]))
           {
               lastDigit = Int32.Parse(line[i].ToString());
               break;
           }
       }

       Overall += firstDigit  + lastDigit;
   }

   return Overall;
}

private int Sum() 
{
   int Overall = 0;

   Console.WriteLine("Enter the calibration document. Enter an empty line to finish.");

   string line;
   while ((line = Console.ReadLine()) != "")
   {
       int firstDigit = 0;
       int lastDigit = 0;

       // Find the first digit
       for (int i = 0; i < line.Length; i++)
       {
           if (Char.IsDigit(line[i]))
           {
               firstDigit = Int32.Parse(line[i].ToString());
               break;
           }
       }

       // Find the last digit
       for (int i = line.Length - 1; i >= 0; i--)
       {
           if (Char.IsDigit(line[i]))
           {
               lastDigit = Int32.Parse(line[i].ToString());
               break;
           }
       }

       Overall += firstDigit  + lastDigit;
   }

   return Overall;
}

7 Replies

Kiel•12mo ago

you're adding the numbers together wrong. if your first digit is 5 and your last digit is 7, you should be adding 57, not 12 Overall += firstDigit + lastDigit; is the problme line

AceChewyOP•12mo ago

Right, that completely went over my head, I need to concatentate them first then parse them

Kiel•12mo ago

alternatively, you can multiply the first digit by 10

AceChewyOP•12mo ago

so firstDigit *10 + lastDigit (which is also more efficient)

Kiel•12mo ago

AceChewyOP•12mo ago

Thanks :) I'm also a little unsure why this doesn't work :

 int Overall = 0;

var map = new Dictionary<string, int> 
{
     { "0"  , 0 },
     { "one" , 1 },
     { "two" , 2 },
     { "three", 3 },
     { "four" , 4 },
     { "five" , 5 },
     { "six" , 6 },
     { "seven", 7 },
     { "eight", 8 },
     { "nine" , 9 },
     { "1"  , 1 },
     { "2"  , 2 },
     { "3"  , 3 },
     { "4"  , 4 },
     { "5"  , 5 },
     { "6"  , 6 },
     { "7"  , 7 },
     { "8"  , 8 },
     { "9"  , 9 },
};

Console.WriteLine("Enter the calibration document. Enter an empty line to finish.");

string line;
while ((line = Console.ReadLine()) != "")
{
    string firstDigit = "";
    string lastDigit = "";

    // Find the first digit
    for (int i = 0; i < line.Length; i++)
    {
        if (map.ContainsKey(line[i].ToString()))
        {
            firstDigit = line[i].ToString();
            break;
        }
    }

    // Find the last digit
    for (int i = line.Length - 1; i >= 0; i--)
    {
        if (map.ContainsKey(line[i].ToString()))
        {
            lastDigit = line[i].ToString();
            break;
        }
    }

    Overall += map[firstDigit] * 10 + map[lastDigit];
}

Console.WriteLine(Overall);

 int Overall = 0;

var map = new Dictionary<string, int> 
{
     { "0"  , 0 },
     { "one" , 1 },
     { "two" , 2 },
     { "three", 3 },
     { "four" , 4 },
     { "five" , 5 },
     { "six" , 6 },
     { "seven", 7 },
     { "eight", 8 },
     { "nine" , 9 },
     { "1"  , 1 },
     { "2"  , 2 },
     { "3"  , 3 },
     { "4"  , 4 },
     { "5"  , 5 },
     { "6"  , 6 },
     { "7"  , 7 },
     { "8"  , 8 },
     { "9"  , 9 },
};

Console.WriteLine("Enter the calibration document. Enter an empty line to finish.");

string line;
while ((line = Console.ReadLine()) != "")
{
    string firstDigit = "";
    string lastDigit = "";

    // Find the first digit
    for (int i = 0; i < line.Length; i++)
    {
        if (map.ContainsKey(line[i].ToString()))
        {
            firstDigit = line[i].ToString();
            break;
        }
    }

    // Find the last digit
    for (int i = line.Length - 1; i >= 0; i--)
    {
        if (map.ContainsKey(line[i].ToString()))
        {
            lastDigit = line[i].ToString();
            break;
        }
    }

    Overall += map[firstDigit] * 10 + map[lastDigit];
}

Console.WriteLine(Overall);

It's late here now so I'll try again later

Kiel•12mo ago

you're only checking a single character in the string, so it will never match on the "word" numbers you'd need to rework the logic that loops from end to beginning to be aware of characters after it

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Advent of Code Day 1