In this article, we will understand how to get key from HashMap using the value. Java HashMap is a hash table based implementation of Java's Map interface. It is a collection of key-value pairs.Below is a demonstration of the same −Suppose our input is −Input HashMap: {Java=8, Scala=5, Python=15} Key: 8The desired output would be −The value of Key: 8 is JavaAlgorithmStep 1 - START Step 2 - Declare namely Step 3 - Define the values. Step 4 - Create a HashMap of integer and string values and initialize elements in it using the ‘put’ method. Step 5 - Define ... Read More

In this article, we will understand how to remove duplicate elements from arrayList. The ArrayList class is a resizable array, which can be found in the java.util package. The difference between a built-in array and an ArrayList in Java, is that the size of an array cannot be modified.Below is a demonstration of the same −Suppose our input is −Input list : [150, 250, 300, 250, 500, 150, 600, 750, 300]The desired output would be −The list with no duplicates is: [150, 250, 300, 500, 600, 750]AlgorithmStep 1 - START Step 2 - Declare namely Step 3 - Define the ... Read More

In this article, we will understand how to update value of HashMap using key. Java HashMap is a hash table based implementation of Java's Map interface. It is a collection of key-value pairs.Below is a demonstration of the same −Suppose our input is −Input HashMap: {Java=1, Scala=2, Python=3}The desired output would be −The HashMap with the updated value is: {Java=1, Scala=12, Python=3}AlgorithmStep 1 - START Step 2 - Declare namely Step 3 - Define the values. Step 4 – Create a hashmap of values and initialize elements in it using the ‘put’ method. Step 5 - Display the hashmap on ... Read More

In this article, we will understand how to iterate over a set. A Set is a Collection that cannot contain duplicate elements. It models the mathematical set abstraction.The Set interface contains only methods inherited from Collection and adds the restriction that duplicate elements are prohibited.Below is a demonstration of the same −Suppose our input is −Input set: [Java, Scala, Mysql, Python]The desired output would be −Iterating over Set using for-each loop: Java, Scala, Mysql, PythonAlgorithmStep 1 - START Step 2 - Declare namely Step 3 - Define the values. Step 4 - Create a hashset of values and initialize elements ... Read More

In this article, we will understand how to iterate over a HashMap. Java HashMap is a hash table based implementation of Java's Map interface. It is a collection of key-value pairs.Below is a demonstration of the same −Suppose our input is −Input Hashmap: {Java=Enterprise, JavaScript=Frontend, Mysql=Backend, Python=ML/AI}The desired output would be −The keys of the Hashmap are: Java, JavaScript, Mysql, Python, The Values of the Hashmap are: Enterprise, Frontend, Backend, ML/AI, AlgorithmStep 1 - START Step 2 - Declare namely Step 3 - Define the values. Step 4 - Create a hashmap of strings and initialize elements in it using ... Read More

In this article, we will understand how to convert the arrayList into a string and vice versa. The ArrayList class is a resizable array, which can be found in the java. util package. The difference between a built-in array and an ArrayList in Java, is that the size of an array cannot be modified.Below is a demonstration of the same −Suppose our input is −Input string: Java ProgramThe desired output would be −The array after conversion from string is: J a v a P r o g r a mAlgorithmStep 1 - START Step 2 - Declare namely Step 3 ... Read More

In this article, we will understand how to convert the linked list into an array and vice versa. The java.util.LinkedList class operations perform we can expect for a doubly-linked list. Operations that index into the list will traverse the list from the beginning or the end, whichever is closer to the specified index.Below is a demonstration of the same −Suppose our input is −The list is defined as: [Java, Python, Scala, Mysql]The desired output would be −The result array is: Java Python Scala MysqlAlgorithmStep 1 - START Step 2 - Declare namely Step 3 - Define the values. Step 4 ... Read More

In this article, we will understand how to get the middle element of linkedList in a single iteration. The java.util.LinkedList class operations perform we can expect for a doubly-linked list. Operations that index into the list will traverse the list from the beginning or the end, whichever is closer to the specified index.Below is a demonstration of the same −Suppose our input is −Input linked list: 100 200 330The desired output would be −The middle element of the list is: 200AlgorithmStep 1 - START Step 2 - Declare a LinkedList namely input_list. Declare five node objects namely head, first_node, second_node, ... Read More

In this article, we will understand how to implement the queue data structure. A Queue is a linear structure which follows a particular order in which the operations are performed. The order is First In First Out (FIFO).Below is a demonstration of the same −Suppose our input is −Input Queue: [150, 300, 450, 600]The desired output would be −After removing an element, the elements of the queue are: [300, 450, 600]AlgorithmStep 1 - START Step 2 - Declare namely Step 3 - Add elements to it using the ‘offer’ method. Step 4 - Display the queue content Step 5 - ... Read More

In this article, we will understand how to implement the graph data structure. we implement the graph data structure we implement graphs in Java using HashMap collection. HashMap elements are in the form of key-value pairs. We can represent the graph adjacency list in a HashMap.Below is a demonstration of the same −Suppose our input is −Number of Vertices: 5 Number of edges: 5The desired output would be −The connections between the nodes of the Graph are: 1 - 2 1 - 3 1 - 4 2 - 4 2 - 5 3 - 4 3 - 5 4 - ... Read More