Question

how to use java ArrayList to get the result?

removing consecutive duplicates

eg [1 2 2 3 2 2 1] ------->[1 2 3 2 1]

Answer 1

Solution Description:

Add elements to input_Array list and then call a function which accepts the array list and returns the array list.

Inside the function declare a temp array list and add the first element of input.

after that run the loop from 0 to size of input_list and check if the current and previous elements are matched or not.if not then add it to temp list.

At last returns the temp Array List .

Code:

import java.util.*;
public class RemoveConsecutiveDuplicates   
{
public static ArrayList<Integer> removeConsecutiveDups(ArrayList<Integer> input_list) //function removeConsecutiveDups() which accepts ArrayList and retunrs it
{
ArrayList<Integer> temp = new ArrayList<Integer>(); //initalize new temp ArrayList
temp.add(input_list.get(0)); //add the starting value of input_list to temp

for(int i = 1; i < input_list.size(); i++) //iterate the loop from 0 to size of ArrayList
{
if(input_list.get(i-1) != input_list.get(i)) //check if the present and previous elements are same if not
{
temp.add(input_list.get(i)); //add to temp list
}
}
return temp; //finally returns the ArrayList
}
public static void main(String args[])
{
ArrayList<Integer> input_list = new ArrayList<Integer>(); //Array List Declaration
input_list.add(1);
input_list.add(2);
input_list.add(3); //add input numbers to input_list
input_list.add(2);
input_list.add(2);
input_list.add(1);
ArrayList<Integer> newList = removeConsecutiveDups(input_list); //call removeConsecutiveDups() functon with passing input_list and store the result
System.out.println("Final List after removing all consecutive duplicates: " + newList); //finally print the result
}
}

Code and Output Screenshots:

Note : if you have any queries please post a comment thanks a lot...always available to help you...