TreeSet Case Insensitive Check

As we know that TreeSet by default store the unique value it doesn’t check case of the value that is being added.

For example if we have a set instance set1 of string type and add value like as follows.

set1.add(“a”);

set1.add(“A”);

Now if we check the size of set1 , it will give size 2 because ASCII value of  ‘a’ & ‘A’ is different, as well as equality check of both value will return false so set1 will add both the value.

It is not amazing it is the default nature of set.

Suppose we have a scenario that set should ignore case sensitive value  and when user add two value like ‘a’ & ‘A’ it should only store one value.

  See the below mentioned example which solve the case sensitive problem.

Set<String> set1=new TreeSet<String>(String.CASE_INSENSITIVE_ORDER);

            set1.add("a");

            set1.add("A");

           

            System.out.println(set1.size());

            System.out.println(set1);

Output :

1

[a]

Reverse of a string in optimized way

Most of the time we came a cross to reverse of a string in interview and interviewer always say it should be optimized.
There are so many ways to reverse a string one of them is mentioned below.

public class StringReverse {
    
    public static void main(String arg[])
    {
        String string="I AM MIKE MORTAN";
        char[] tempCharArray=string.toCharArray();
        int start,end=0;
        end=tempCharArray.length-1;
        for(start=0;start<end;start++,end--)
        {
            char temp=tempCharArray[start];
            tempCharArray[start]=tempCharArray[end];
            tempCharArray[end]=temp;
        }
        
        System.out.println(new String(tempCharArray));
    }

}

In this way we will reverse the string in half of the iteration of a given string, rather than traversing complete string from start to end.