Three values in a row in a 2d array c#

Question

I'm trying to get my program to check if my 2d array has 3 of the same value next to each other.

I currently have this code, but it is returning true whenever I get to count == 2 (sorry that its in dutch):

    bool ScoreRijAanwezig(RegularCandies[,] speelveld)
    {
        bool rij = false;
        int count = 0;
   `    for (int i = 0; i < speelveld.GetLength(0); i++)
        {
            {
                for (int j = 0; j < speelveld.GetLength(1) - 2; j++)
                {
                    if (speelveld[i, j] == speelveld[i, j + 1])
                    {
                        count++;
                        if (speelveld[i, j + 1] == speelveld[i, j + 2])
                            count++;
                        if (count >= 3)
                        {
                            rij = true;
                            count = 0; 
                        }
                    }
                }
            }
        }
        return rij;
    }

How do I get it that it only returns true whenever the count hits 3 or bigger.

Dmitrii Bychenko · Accepted Answer · 2018-12-03 12:07:47Z

1

If I've understood you right, you are looking for at least 3 equal values in a row:

[1 2 3 4 5
 5 7 8 9 1
 3 6 6 6 7   <- three 6 in a row (what we are looking for)
 3 7 8 9 0
 3 5 3 5 3]  <- just three 3, don't count
 ^
 three 3 but in a column, don't count

Let's implement it

// static: we don't use "this" in the method 
static bool ScoreRijAanwezig(RegularCandies[,] speelveld) {
  // row is too short 
  if (speelveld.GetLength(1) <= 2)
    return false;

  // scan each column
  for (int i = 0; i < speelveld.GetLength(0); ++i) {
    // we have at least 1 value in a row - it's a leftmost value
    RegularCandies current = speelveld[i, 0];
    int count = 1;

    // we are scanning row:
    //  if we have the same value, let's increment check count
    //  if not, let's start from the value again
    for (int j = 1; j < speelveld.GetLength(1); ++j) {
      if (current == speelveld[i, j]) {
        // increment and check: do we have 3 in the row?
        if (++count >= 3) 
          return true;
      }
      else {
        // sequence is broken, let's start again with count = 1 
        current = speelveld[i, j];
        count = 1; 
      } 
    }
  }

  // entire array has been scanned, no three in the row found
  return false;
}

edited Dec 3, 2018 at 12:07

answered Dec 3, 2018 at 11:13

Dmitrii Bychenko

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2 Comments

Jordy Pouw Over a year ago

Thanks for your comment and help, but one small question the RegularCandies current = speelveld[i, 0]; gives back the parameter where it currently is or does it something different?

Dmitrii Bychenko Over a year ago

current is a candidate value we check (if it repeats 3 times). We start from hypothesis that the leftmost value - speelveld[i, 0] repeats 3 times in a row: 4 4 4 ... if we fail, e.g. 4 4 2 ... we start testing 2 if we have: 4 4 2 2 2 ... then, say, on next failure 4 4 2 1 ... we keep on with 1 etc.

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