Find 3 duplicates next to each other

Question

 int count = 0; 
    for (int i = 0; i < arr.length; i++) { 
        for (int j = 0; j < arr.length; j++) { 
         if (arr[i] == arr[j] && i != j) { 
            return false; 

         }else count++; 
      } 
    } return (count == 3);

Task: Given an integer denoting the size of the array.Fill array with integers and return true if array contains duplicate 3 times next to each other. This code does not Works fine. Given true if found duplicates 2 times.I need three times,and next to each other!! Some1 could help me please?!

What's the problem with comparing the values at i, i+1 and i+2? — Thomas
– Thomas, Commented Mar 14, 2017 at 13:13
Think about what your code does: it iterates over the array n + 1 times, i.e. once for the outer loop and once for each of the n elements. You then increase count if either the indices are the same or the values are not. What do you think count would express in that case? — Thomas
– Thomas, Commented Mar 14, 2017 at 13:17

Codeinator · Accepted Answer · 2017-03-14 13:14:13Z

5

What's about this:

for (int i = 0; i < arr.length - 2; i++) { 
     if (arr[i] == arr[i + 1] && arr[i] == arr[i + 2]) { 
        return true; 
     }
}
return false;

answered Mar 14, 2017 at 13:14

Codeinator

6991 gold badge8 silver badges29 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Bathsheba Over a year ago

UV'd. Picky but I'd prefer i = 2; i < arr.length as that will work better in languages like C++ which tend to use unsigned types for sizes.

szarospista Over a year ago

Thank you very much! You are very helpfuly!!

szarospista Over a year ago

But,could you explain me,why i = 2 in for loop?

szarospista Over a year ago

If i give n = 6(denoting the numbers of array) the program give me back error.And does not working.

szarospista Over a year ago

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 6 at Main.isContainDistinct(Main.java:26) at Main.main(Main.java:13)

|

drink-a-Beer · Accepted Answer · 2017-03-14 17:33:55Z

Solution using ArrayList to store the matching numbers,

    int[] arryOne={1,2,3,4,4,4,5,5,5,6,6,7,7,7,8,9,9,9,19,19,19,21,21,30,45,10,10,10};
    ArrayList<Integer> arryTwo=new ArrayList<Integer>();
    for (int x=0;x<=arry.length-1;x++)
    {
        if(arryOne[x]==arryOne[x+1] && arryOne[x]==arryOne[x+2] &&  x!=arry.length-2)
        {
            arryTwo.add(arry[x]);
            x=x+2;

        }       
    }
    System.out.println("The number which is repeating three times in the array is = ");
    for (int valInArrayList: arryTwo)
    {
        System.out.print(valInArrayList + ", ");
    }

Augustin Bocken · Accepted Answer · 2017-03-15 09:15:19Z

-1

for(int i=0;i<arr.length-2;i++){
   if((arr[i]==arr[i+1])&& (arr[i]==arr[i+2])){
      return true;
    }
}
return false;

This way, we only check the array once, and this improve performances. What we do here in plain english is : "Check if a number is equal to the two following him", and we stop before going out of the array (this is what array.length-2 is for)

Ex: for an array of 6 numbers, we will check

[0,1,2]  
[1,2,3] 
[2,3,4]  
[3,4,5]

edited Mar 15, 2017 at 9:15

answered Mar 14, 2017 at 13:16

Augustin Bocken

3794 silver badges19 bronze badges

3 Comments

DimaSan Over a year ago

While this code snippet may solve the question, including an explanation really helps to improve the quality of your post. Remember that you are answering the question for readers in the future, and those people might not know the reasons for your code suggestion.

Bathsheba Over a year ago

If you remove the snarky comment at the beginning then I'm sure folk will retract downvotes. I will.

Bathsheba Over a year ago

Downvote converted to upvote. Thank you for editing.

Collectives™ on Stack Overflow

Find 3 duplicates next to each other

3 Answers 3

7 Comments

Comments

3 Comments

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

7 Comments

Comments

3 Comments

Related