How to find duplicate values in array in java. See full list on stackoverflow.

How to find duplicate values in array in java. g. Jul 25, 2018 · I want to find out the duplicate element and there index number from an array. an array with rows = columns. out. Jul 23, 2025 · As we know that the HashSet contains only unique elements, ie no duplicate entries are allowed, and since our aim is to remove the duplicate entries from the collection, so for removing all the duplicate entries from the collection, we will use HashSet. Finding duplicate elements in an array is a common problem in programming, especially in data processing tasks. So the output should Jul 3, 2025 · Java Program to remove duplicates from integer array without Collection In this program, we have not used any collection class to remove duplicates, earlier, I had shown you a way to remove duplicates from ArrayList, which was using LinkedHashSet. Learn how to find duplicate values in a JavaScript array with this comprehensive guide, including examples and step-by-step instructions. For example, if an array is {1, 2, 3, 2, 3, 5} then the program should print the elements {2, 3} as these elements appeared in the array more than once. Master efficient techniques for duplicate detection in Java. I want to figure out is there any duplicate entries in this list. In this quick tutorial, you’ll learn how to find duplicates in an array using JavaScript. It's when there are multiple identical elements in a collection. This implementation differs from HashMap in that it maintains a doubly-linked list running through all of its entries. I was thinking of doing a Binary Search for finding x in the sorted array, and then checking all values before and after this index, but then if the array contained all x values, it doesn't seem like it would be that much better. Nov 2, 2012 · Since the Binary Search will finish after the first "find" of a particular value. Learn how to find the duplicate values in an array in Java and print those duplicate values. So far I did Dec 11, 2018 · A better way (both time complexity and ease of implementation wise) is to remove duplicates from an ArrayList is to convert it into a Set that does not allow duplicates. Feb 15, 2023 · In this tutorial, we will see “How to find Duplicate Element in an Array using Java 8?”. Apr 3, 2024 · Each object in the array holds an integer value. LinkedHashSet, Stream API, and manual methods with working code you can copy-paste. Hence LinkedHashSet is the best option available as this do not allows duplicates as well it preserves the insertion order. Nov 28, 2020 · I want to find duplicated values on a String . Sep 2, 2015 · Possible Duplicate: Easiest way to find duplicate values in a javascript array How do I check if an array has duplicate values? If some elements in the array are the same, then return true. frequency At the end of the article, we Jul 17, 2022 · Few simple examples to find or count the duplicates in stream and remove the duplicates from stream in Java 8. Jul 12, 2025 · There are many methods to find duplicate elements in a Stream: Using Set: Since Set has the property that it cannot contain any duplicate element. There is only one duplicate element, find the duplicate element in O (n) time complexity and O (1) space. Jun 14, 2024 · The Problem Given an array of integers, we need to count how many times each integer appears in the array. util. Feb 12, 2022 · For finding duplicates, iterate through original List and remove elements by comparing elements in unique list and store into new Set using collect (Collectors. This linked list defines the iteration ordering, which In this tutorial, we'll explore different methods for finding duplicates in Java lists, focusing on both the basics and advanced techniques. Different ways are explained. Additionally, For each element in the array, we can compare it with every other element to check for duplicates. Mar 15, 2020 · This article shows you three algorithms to find duplicate elements in a Stream. For example: // Duplicates are {1, 4} List<Integer> numbers = Arrays. If none of the values are the same, increment your index and do the same for the next row. In this tutorial, we are going to solve this problem using Java hash table and set data structure. Can you solve this real interview question? Contains Duplicate - Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. Removing duplicate elements from an array is a common operation that can be easily accomplished using sets. Jul 5, 2024 · This program demonstrates how to find duplicate elements in an array using Java. Can you solve this real interview question? Find All Duplicates in an Array - Given an integer array nums of length n where all the integers of nums are in the range [1, n] and each integer appears at most twice, return an array of all the integers that appears twice. Jul 11, 2024 · Checking for duplicates in an array is a common problem that can appear in coding interviews. here is my solution. Identifying duplicates in a list is a common task in software development, often necessary for data Jun 13, 2024 · This program efficiently counts and prints the occurrences of duplicate values in an array using a HashMap, demonstrating a practical approach to solving this problem in Java. Create one Scanner object to read user input. Dec 31, 2014 · I am stuck in the following program: I have an input integer array which has only one non duplicate number, say {1,1,3,2,3}. com Mar 7, 2025 · In Java, finding duplicate values in an array is a common task often approached with various techniques. addAll(set); Of course, this destroys the ordering Mar 27, 2012 · Possible Duplicate: How to find a duplicate of length 5 in a single array. distinct(). e. toSet ()) method which results into duplicate list FindDuplicatesUsingDistinctMethod. Set a HashSet that stores the unique values of an array. Feb 21, 2014 · 1 Go through each value in the row. You can still use that solution if the interviewer doesn't mention it without Collection specifically. Example to Efficiently Remove Duplicates How about this one, only for the sorted Array of numbers, to print the Array without duplicates, without using Set or other Collections, just an Array: public static int[] removeDuplicates(int[] array) { Dec 28, 2014 · I am trying to list out duplicate elements in an integer list using Streams of JDK 8. I suggust: make a new collection, e. By converting the array to a Set, you immediately remove all duplicates due to the uniqueness property of Set. Approach: Get the stream of elements in which the duplicates are to be found. We'll use the Stream API, Collectors and Collections. Learn how to efficiently find and print duplicate values in an array list using Java with code examples and common mistakes to avoid. How can we detect this duplicate in time O (n)? For example, an array of 4,1,2,3 would become 4,1,2,2. We will learn this using two different approaches :. We want to make an algorithm that finds either of these duplicates and returns true when it does. Below is the discussion of this program by two approaches: Jan 25, 2025 · Java program to find duplicate strings in an Array This program provides a simple and efficient way to identify and count duplicate strings in an array. Jul 15, 2025 · Given a string, the task is to write Java program to print all the duplicate characters with their frequency Example: Input: str = "geeksforgeeks" Output: s : 2 e : 4 g : 2 k : 2 Input: str = "java" Output: a : 2 Approach: The idea is to do hashing using HashMap. In order to find duplicates, we are going to use several techniques. There is only one repeated number in nums, return this repeated number. The class also offers constant Jul 19, 2024 · Finding duplicates in an array of objects is a common task in JavaScript, especially when dealing with data manipulation and validation. I write down a code for that. put(2, "a"); map. Mar 14, 2022 · Using a Set To find duplicates in an array using JavaScript, utilizing a Set is an efficient and modern approach. Learn how to find and select duplicate values from a list in Java using efficient techniques and code snippets. Optimize your data structures and improve your Java programming skills. count() Is it the best way? Jul 23, 2025 · Here are the different methods to find duplicate elements in the array 1. I know there are other solutions to find that but i want to use HashMap. The total running time would be O (n log (n)). Examples : Input : arr[] = {1, 4, 3, 4, 2} Output : 4 Input : arr[] = {1, 3, 2, 1} Output : 1 Approach: Firstly, the constraints of this problem imply that a cycle must exist. Here the condition is no loop statements. Jul 3, 2021 · Learn how to check if an array contains duplicate values using indexOf(), set object, and iteration in JavaScript. Feb 17, 2023 · 2. What is the best way to iterate an array in efficient way? Or else can we use any other Java collection object to find the duplicates with less number of iterations or less time complexity? Jan 8, 2024 · Learn a few ways to remove duplicate values from a Java HashMap. Given an array that may contain duplicates, print all repeated/duplicate elements and their frequencies. Example: int [] array = { 0, 7, 9, 1, 5, 8, 7, 4, 7, 3}; 7 is located in three different locations at index 1, 6, and 8. This will guide you through the process of identifying duplicate objects in an array using various techniques. clear(); yourList. Dec 26, 2016 · The one very special case in which you might pick Chris' solution would be if you want to use the method to separately de-duplicate thousands of small arrays and expect to find a duplicate typically less than 10 items in. Mar 3, 2024 · Finding Duplicates using java streams Using Set. Thanks for the help. Jul 23, 2025 · Arrays are a fundamental data structure in Java that stores data of the same type in contiguous memory locations. length; i++) { result ^= array[i]; } System. This way has too many loops and I am sure there must be an easier way to find duplicates rather than going through this massive looping process. add () method: If the element is present in the Set already, then this Set. Example: [0, 2, 0] would return 2, [0, 0, 0] would return 3, [0, 1, 2] = 0 So far I have it working for when all three items are equa Learn how to check for duplicate elements in a Java array using nested loops, HashSet, and sorting. sort() method. By Static Initialization of Array Elements By Dynamic Initialization of Array Elements Method-1: Java Program to Find the Duplicate Values of an Array of String Values By Static Initialization of Array Elements Approach: Create a string array. Approach: Get the ArrayList with duplicate values. Thank you all for your help, I'll try your tips. Jul 31, 2015 · As a part of the Java interview question paper I have got following issue to solve. Jul 22, 2025 · The main idea is to first sort the array so that duplicate elements appear next to each other. Now, let's understand the logic behind each of those solutions in little more detail. Dec 27, 2024 · Let’s see different ways to find duplicate string value in a string array. Words with no duplicates should be displayed alone The output needs to be like this anps anps anps bbo ehllo I have tried while, for loops but the logic seems impossible. Let’s see them one by one. add() Collectors. groupingBy Collections. One of the common challenges in software development is efficiently finding duplicate values within collections, such as arrays. Step to find duplicate in String [] Array : Create String [] Arrays consisting few duplicate element/objects First convert String [] Arrays into List And then convert List into Set, as directly converting String Arrays to Set is not possible Get length of String Arrays using length property of Arrays Similarly get size of Set / HashSet object using size () method Finally compare Arrays Apr 4, 2025 · Explore various ways to calculate the count of duplicate elements in a list. put(3, "b"); I want to save the duplicate value in a variable named String duplicate. We have also managed to do this in O (n) as this is just a single pass of entire array. One straightforward method involves iterating through the array and comparing each element with every other element to identify duplicates. An element is considered to be duplicated if its frequency is more than 1, in which case the method returns that element. Then iterate through the keys and find the ones with multiple values. I tried with recursion method but it not working out. It can also be used to remove duplicate values from an array. distinct () method eliminates/removes duplicate from Original Arrays and store into new Arrays using toArray (String []::new) method which results into unique elements in an Arrays For finding duplicates, Create a new List using original Arrays Iterate through new List and remove elements by comparing elements in unique Arrays Sep 26, 2017 · I am trying to write a code which will find the duplicate value in an array. The easiest way to remove repeated elements is to add the contents to a Set (which will not allow duplicates) and then add the Set back to the ArrayList: Set<String> set = new HashSet<>(yourList); yourList. java ? Nov 9, 2022 · Learn to find, count and remove duplicate elements from an array in Java using Streams, Map and Set from the Collections framework. Create a hashMap of type {char, int}. Find the Duplicate Number - Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive. Then, a single pass is made to compare each element with its previous one. To be more precise, the frequency of each element in the array is stored using an unordered map. Overview In this tutorial, We'll learn how to find the unique values from two lists and how to find all common or duplicates values from two lists. May 5, 2015 · In java 8, what's the best way to check if a List contains any duplicate? My idea was something like: list. Jan 10, 2021 · Solution Initialize max and second_max with the lowest possible value Integer. Using a HashMap allows us to store each integer as a key and its count as the value. So, far I have written below code: public static void main (String [] args) { // TODO Auto-generated method stub Sep 17, 2014 · I'm trying to count how many duplicate items are in an array. In this tutorial, we will learn how to find duplicate elements in an array of strings. Hashtable; public class test { 4 Use a MultiMap to store each value as a key / value set. In this post, we will learn to find duplicate elements in array in java using Brute Force method, using Sorting method, using HashSet, using HashMap and using Java 8 Streams. Example program are demonstrated with Set, a new List with contains() method and Java 8 Streams. Jul 23, 2025 · The main idea is to first sort the array arr[] and then iterate through it to check if any adjacent elements are equal. Using For Loop Let’s see how you can find duplicates in an array using for loop. Java I am trying to see if there are any duplicates in the array. Loop through each value of the array If the HashSet of unique values contains the current value: Increment the duplicate Count Oct 15, 2008 · If you don't want duplicates in a Collection, you should consider why you're using a Collection that allows duplicates. For every value, check and see if any of the values after that value are the same. If the value is the same, return true (you've found a duplicate). The Set object lets you store unique values of any type, whether primitive values or object references. For finding duplicate values in JavaScript array, you’ll make use of the traditional for loops and Array reduce method. See full list on stackoverflow. But I am bit wonder whether how can I implement it without any Collection or intermediate Array. containsValue(value). May 27, 2019 · A Quick Guide to how to remove duplicate objects from ArrayList. Because each GeeksforGeeks | A computer science portal for geeks Jul 23, 2025 · The basic idea is based on the hash map to solve the problem. we can collect them. If Jul 19, 2023 · Finding duplicate elements in a stream of data is one of the common questions that is asked in Java interviews and even in the exams of many students. How to print duplicate elements in array of strings? If any addition failed, means that element is already added, we will print that element as duplicate. Like, Share and Subscribe to my YouTube ch Mar 4, 2025 · Given an array arr [] of N+2 elements. Jul 1, 2025 · In the first paragraph, I have given you a brief overview of three ways to find duplicate elements from Java array. In some cases, it’s necessary to identify duplicates in a List, and there are various methods to achieve this. 2. Pls anyone help m Jul 4, 2025 · In Java, duplicate elements refer to having the same value or content appearing more than once in a data structure like an array, list, or set. The algorithm iterates through the array and uses a HashSet to track seen elements. Traverse the string, check if the hashMap already contains the traversed character or not. Algorithm Steps of given approch : Create an unordered map called freq to store the Write a Java Program to Count Array Duplicates with an example or how to write a program to find and count the duplicates in a given array. We will see first using plain Java and then Java 8 Lambda-based solution. May 9, 2025 · Java exercises and solution: Write a Java program to find duplicate values in an array of integer values. I’ll provide a step-by-step explanation of the logic used in the program. This method can be used even if the array is not sorted. All elements of the array are in the range of 1 to N. Sorting helps eliminate the need for extra space like maps or arrays, making the logic clean and space-efficient. Jan 21, 2019 · There are many methods through which you can find duplicates in array in java. size() != list. Using Nested For In Loop The forin loop is typically used to iterate over the keys of an object or the indices of an array. This is for a square 2D array, ie. Sep 8, 2023 · Approaches to Identify Duplicate Elements in Array in Java Using Nested Loops One approach to identify duplicate elements in an array in Java is by using nested loops. As we traverse the sorted string, we increment a counter for each matching character, and only print those with count > 1. Then clear array, iterate through set and add each element to array. Since the array is now in order you can print the duplicates after each number switch! If this is for an assignment go ahead and google bubble sort and implement it as a method. Sep 20, 2023 · In this tutorial, we'll go over how to find duplicate elements in a Java Stream from a list, map or set. So if we add the elements in a Set, it automatically discards the duplicate elements while addition itself. But, the numbers in the array are from 0 to n-1, and the input array has length n. In this count duplicate array number example, we used a while loop to iterate Dup_Count_arrr array, count duplicate items (item shown more than once), and print the total. There are a variety of functions in Java that simplify that process. Feb 11, 2022 · Java – Different ways to remove duplicate elements from Arrays Java – How to find duplicate in String Arrays ? 1. If no duplicates are found after traversing the entire array, the function returns false. This program encompasses all the three ways we have discussed so far. I want the output a. An array can contain duplicate values as well. Oct 22, 2013 · 0 Iterate through array (via iterator, not foreach) and remove duplicates. So I should find whether the Map has duplicate values. That Java program finds or duplicates elements from the array. Aug 27, 2025 · Remove duplicates from Java arrays in 5 minutes. Feb 6, 2023 · The array above has two duplicates, numbers 1 and 3 appear twice in the array. We will use ArrayList to provide stream of elements including duplicates. Otherwise it would return false. While this method is straightforward, it may not be the most efficient for large arrays. May 4, 2023 · Learn how to find duplicate elements and the frequency of repeated elements in a Java array using nested loops, sets, streams, and hash tables. Oct 10, 2023 · Efficiently delete duplicates from a Java HashMap with different approaches and code examples. Find duplicate elements in an array using the sorting method In this method, we are sorting the first using the Arrays. In Java 8, finding duplicate elements in a Stream is easy and efficient using the filter() method and a Set to track previously seen elements. All you need to do is to convert your array Nov 26, 2016 · I have an ArrayList with duplicate string values and want to make the duplicates unique by appending a count. Basically i have a list of users, and there should be no duplicate entr Aug 9, 2024 · Find Duplicate Elements in Array: In this blog post, we will talk about one of the very famous interview questions, whether you are a refresher or an experienced one. Examples: Input: arr = [4, 2, 4, 5, 2, 3, 1], N = 5 Output: 4 2 Explanation: The above array has n + 2 = 7 elements with all elements occurring once except 2 and 4 which occur twice. Every row will take at most n (n+1)/2 comparisions which isn't wonderful. I have one array String [] array = {anps, anps, anps, bbo, ehllo}; I need to be able to go through the array and find duplicates and print them on the same line. Oct 7, 2024 · When working with collections in Java, a common task is finding duplicate elements. The frequency can be retrieved by dividing the a % n'th element by n. Learn how to detect duplicate values in a primitive Java array with step-by-step examples and code snippets. - The inner loop compares it with all the numbers that come after it. Finding duplicates in a Java list? That’s actually a bit more complicated, but finding the dupes in a Lists is by no means an impossible task. With the introduction of the Stream API in Java 8, performing such operations has become both efficient and elegant. Question:- Count 3 I have to locate and list all duplicate index values in array. Here’s a Java program that demonstrates how to implement a method to find duplicate elements in an ArrayList. 1 If your array satisfied these two conditions -: Only duplicates and single value allowed (No triplicate or greater allowed) There should only be one unique value in the array // Use Bitwise 'exclusive or' operator to find unique value int result = array[0]; for (int i = 1; i < array. Then, we iterate over an array to check if the next adjacent element is a duplicate or not. add () returns false. OR Iterate through array and add all elements to LinkedHashSet, it isn't allows duplicates and keeps order of elements. Nov 27, 2020 · The frequency of an element in an array is the count of the occurrence of that particular element in the whole array. As treeset does not support duplicate entries, we can easily find out duplicate entries. So, the input array itself can be used as a hash map. Example 1: Input: nums = [1,2,3,1] Output: true Explanation: The element 1 occurs at the indices 0 and 3. Map<String, Integer> counts = new LinkedHashMap<String, Integer>(); About LinkedHashMap: Hash table and linked list implementation of the Map interface, with predictable iteration order. asList(new Integer[]{1,2,1,3,4,4}); To remove duplicates we can use the distinct() method. Once you have gone through all values in the original arrays, print whatever is in the duplicates collection. println May 23, 2019 · 1. !! what i am missing on the last part ? i want to get jus Oct 18, 2024 · Finding the first duplicate in an array can be done using different strategies, each with its time and space complexity trade-offs. You can count the number of duplicate elements in a list by adding all the elements of the list and storing it in a hashset, once that is done, all you need to know is get the difference in the size of the hashset and the list. MIN_Value Then go through your array and check for each element if it is greater then the max_value -> When yes reassign your max_value with a [i] and reassign your second_max_value with max_malue Dec 17, 2020 · 0 How to find the duplicate element in an array which is having lacks of elements? If I iterate the array for lacks of times the performance will became slow. Sep 13, 2020 · Is there any simple way to identify duplicate values in a HashMap? HashMap<Integer, String> map= new HashMap<Integer, String>(); map. The flip side of this algorithm is that the elements of the array are modified but we have not used any additional storage. Learn to remove duplicate elements from an ArrayList using different techniques such as HashSet, LinkedHashSet, and using Java 8 stream. Jul 11, 2025 · Given an array arr [] containing n integers where each integer is between 1 and (n-1) (inclusive). But what about finding the duplicated elements? Jan 9, 2024 · It’s easy to remove duplicates from a list in Java. We will use the unique property of the Java collection class Set which doesn’t allow duplicates to check the java array for duplicate elements. Sort the array to be ready for comparison. Nov 23, 2018 · 1. Different Ways to Find Duplicate Elements in an Array There are various ways of doing it: Mar 18, 2016 · A LinkedHashMap will retain order. If a pair of adjacent elements is equal, the function returns true, indicating the presence of duplicates. Jan 20, 2025 · Unlocking Java: Finding the First Duplicate Index in Arrays Java is a robust and versatile programming language cherished by developers worldwide. You can do this by passing the array into the Set constructor the convert the produced set back to an array. So, I would ge Jul 23, 2025 · Given an array, the task is to remove the duplicate elements from an array. Let's see how we can do it by Mar 12, 2013 · I have an array of string, which holds the list of strings. If so, how can this new way work - and how can I manipulate it to work to find duplicate values in the rows as well. The simplest method to remove duplicates from an array is using a Set, which automatically eliminates duplicates. It highlights key Java concepts such as hash-based data structures and string processing. The output should show the non duplicate element i. Display the array. While traversing the array, if an element a is encountered then increase the value of a % n'th element by n. Jun 12, 2025 · This makes it easier to count consecutive duplicates in one pass. In this blog post, we will not only tackle how to find the first duplicate index in an array but also delve into the . In this blog post, I’ll walk you through various ways to find duplicate elements in a stream using Java, providing explanations and code examples. Learn effective methods to find duplicate values in the rows and columns of a 2D array using Java with code examples and solutions. Let’s take a look into the program first : Declare one String array variable to store all user input strings. a HashSet, and add duplicate values to that instead of printing them. If it does, you have already printed that number, so you don't need to print it again. How to remove custom objects from ArrayList. - If a match is found, we print it as a duplicate. Example: Jul 27, 2015 · It groups together all the numbers in the array into a map where the number is the key and the frequency of that number is the value. How to find duplicates in a Java List The most common approaches to removing duplicates from a List in Java include the Nov 21, 2016 · Can anyone help me to provide the code for finding duplicate values from the array. Nov 30, 2014 · A better solution would be to sort the two arrays - O (n log (n)) and then find the duplicates in a single iteration over both sorted arrays - O (n). A HashMap may have duplicate values (but not duplicate keys), but I want to display a value only once. Feb 10, 2023 · Do you want to identify duplicates elements from Java List? Finding Duplicate Elements in a Java List. And all elements occur once except two numbers which occur twice. Remove duplicate elements from Arrays : Initially, there is a String [] Array with duplicate elements First step is to iterate through original String [] Array with duplicates Use distinct () method of Stream API to remove duplicate String elements and then invoke toArray Oct 9, 2020 · A quick and practical guide to remove all duplicate values from Array in java without using Set. Set. Find duplicate value in an array in java example : Simplest way to find duplicate entries in an array is to add array entries to the TreeSet. Dec 23, 2022 · Find All Duplicates in an Array Given an integer array nums of length n where all the integers of nums are in the range [1, n] and each integer appears once or twice, return an array of all the Nov 3, 2019 · Here is our complete Java program to find out the duplicate numbers in a given array in Java. Thanks! Jul 2, 2015 · Set variables storing the number of duplicates found (0), and the maximum number of duplicates (0). Mar 10, 2023 · Using Set to Remove Duplicates The Set object is a built-in object in Javascript that allows you to store unique values of any type. Use set for find duplicates. Apr 7, 2025 · Checking Array for duplicate elements Java In this Java tutorial, we will see a couple of ways to find if an array contains duplicates or not in Java. Jun 22, 2022 · In this tutorial, we will write java programs to print the duplicate elements of an array. Nov 27, 2023 · 2. The HashSet class implements the Set interface, backed by a hash table which is actually a HashMap instance. Sep 24, 2020 · 3 You need a way of logging which numbers have already been identified as duplicates. Find the two repeating numbers. GeeksforGeeks | A computer science portal for geeks Aug 1, 2011 · 10 I want to display the values in a HashMap. put(1, "a"); map. Before Java 8 : Iterate through values of Map entries using enhanced for-loop and then collect it to another Map with, Key as Duplicate Value Value as Duplicate Count of Map Values Finally, print duplicate count more than 2 using enhanced for-loop & if-condition to the console GetDuplicateCountOfMapValues. Explanation: We go through the array one element at a time. java ? In this video we see how to write a Java Program for Finding Duplicate Values Count In Numeric Array using HashMap. Jul 15, 2025 · Approch 3 : The given code use a hashing technique to locate duplicates in an array. We then keep only the key/value pairs who have a value > 1 (The duplicates). stream(). Mar 3, 2019 · Write a program find duplicate elements in an array. This guide will show you how to create a Java program that identifies and displays duplicate elements in an array. Whether you're a beginner learning about data structures or an experienced programmer looking for efficient algorithms, this guide has something for you. public static void main (String [] args) { List<String> list = new ArrayList< In this tutorial, we'll discover how to find duplicates within an array in JavaScript, as well as how to remove the duplicates. In this post, we’ll explore different ways to solve the “Contains Duplicate” problem using Java. Aug 27, 2023 · Problem Statement: Implement a method to find duplicate elements in an ArrayList in Java. Apr 22, 2022 · Stream. Note: This I am trying to have a method (duplicates) return true if a given array called x (entered by user in another method), contains duplicate values. In this example, the program finds 2 twice and 1 twice, so it prints them as duplicates. import java. Jan 5, 2023 · In Java, Array is a non-primitive data type which stores values of similar data type. Java provides several ways to find duplicate elements, we will focus mainly on two ways: the first Dec 12, 2023 · Discover 5 Effective Methods in Java to Remove Duplicates values from an array while Preserving the Original Order. A List is a collection of elements that can contain duplicates. So, the number of times an element is present in an array, that is called frequency of the element in the array. Please refer to the Java tutorial. - The outer loop picks a number (like the first 1). It works well but only fail to generate exact output when number of duplicate element more May 4, 2021 · In this quick tutorial, I show you how to find duplicates in List in Java. Let's say I have the following two arrays: int[] a = [1,2,3,4,5]; int[] b = [8,1,3,9,4]; I would like to take the first value of array a - 1 - and see if it is contained in array b. Jul 10, 2020 · Conclusion We have traversed the entire array and the list of duplicates has 2 elements: 10 and 1. As per the problem statement we have to detect the elements which are repeating in an array and print its frequency. You have an array of numbers from 0 to n-1, one of the numbers is removed, and replaced with a number already in the array which makes a duplicate of that number. However, in this article, we will learn how to remove duplicates from an array in Java without using a set, in an efficient manner. By "duplicate", the object would have the same integer value. May 27, 2018 · Find duplicate value in array list and print the duplicated value Asked 7 years, 2 months ago Modified 3 years ago Viewed 41k times May 9, 2025 · Java exercises and solution: Write a Java program to find duplicate values in an array of string values. Aug 13, 2019 · 0 Without using Hashmaps, I think your best option would be to first sort the array and then count the duplicates. The code in Java and Kotlin is quite simple but you need to know the algorithm Mar 16, 2018 · If all you can use is a loop: when you find a value you think is a duplicate, loop through from 0 to i-1, checking if it contains the same value as array[i]. I know we can iterate over the Map and use the return boolean of map. hwukb tdbzeg ztogpu esbjjk iyd tdrm itdv zuknz kdlich toh