Question

I have an integer array with five values, sorted in ascending order with no duplicates. I want to check if three of the five values that are in the array meet the requirement that they are in a sequence but don’t all have to.

If three of the group of numbers below are in the array of five numbers the requirement is met:

(1, 2, 3, 4)
or
(5, 6, 7, 8)
or
(9, 10, 11, 12)
etc.

So the following arrays return true:

EXAMPLES:
(1, 2, 3, 18, 40)
or
(2, 3, 4, 20, 34)
or
(1, 3, 4, 7, 12)
or
(9, 11, 12, 31, 51)

While the following arrays return false:

EXAMPLES:
(3, 4, 5, 11, 29)
or
(15, 16, 17, 33, 42)
etc.

The “rule” is that three numbers in the array of five numbers must be within the respective range, 1, 2, 3, 4 or 5, 6, 7, 8 etc. but I don’t know how to go over this

Could someone please help me with this?

I will be forever grateful!

EDIT (since as a new user I can’t post an answer to my own question so soon):

Okay, I have found a partial answer: First I check if three cards have the same rank.

I check if cards 1 to 3 have the same rank. If not, I check if cards 2 to 4 have the same rank. If not, I check if cards 3 to 5 have the same rank. Here is my code:

// check
if (tempArray[0] == (tempArray[1] - 1)) {
    System.out.println("1. and 2. card match");
    if (tempArray[1] == (tempArray[2] - 1)) {
        System.out.println("2. and 3. card match");
        // three cards of same rank, starting from the first
        if (...) {
            isThreeOfAKind = true;
        }
    }
} else {
    System.out.println("1. and 2. card DO NOT match");
    // toak could start from the second card
    if (tempArray[1] == (tempArray[2] - 1)) {
        System.out.println("2. and 3. card match");
        if (tempArray[2] == (tempArray[3] - 1)) {
            System.out.println("3. and 4. card match");
            // three cards of same rank, starting from the second
            if (...) {
                isThreeOfAKind = true;
            }
        }
    } else {
        // toak could start from the third card
        System.out.println("2. and 3. card DO NOT match");
        if (tempArray[2] == (tempArray[3] - 1)) {
            System.out.println("3. and 4. card match");
            if (tempArray[3] == (tempArray[4] - 1)) {
                System.out.println("4. and 5. card match");
                // three cards of same rank, starting from the third
                if (...) {
                    isThreeOfAKind = true;
                }
            }
        }
    }
}

Now you notice that I left out the if clauses. There I have to check if the numbers are within the range (1-4, 5-8, 9-12, etc.) but I have no idea.! But the code is still faulty because for example 1, 3, 4 are not recognised as the same ranks even though it’s valid

Answer 1

public boolean check3InARow(int[] array) {
  int currentResult = (array[0] - 1) / 4;
  int countCurrentResult = 1;
  for (int i=1; i < array.length; i++) {
    if (((array[i] - 1) / 4) == currentResult) {
      countCurrentResult++
      if (countCurrentResult == 3) return true;
    } else {
      currentResult = (array[i] - 1) / 4;
      countCurrentResult = 1
    }
  }
  return false;
}