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Method reference is a simplified form of a lambda expression that can execute one method. It can be described using "::" symbol. A reference to the instance method of a particular object refers to a non-static method that is bound to a receiver.SyntaxObjectReference::instanceMethodNameExample - 1import java.util.*; public class InstanceMethodReferenceTest1 { public static void main(String[] args) { String[] stringArray = { "India", "Australia", "England", "Newzealand", "SouthAfrica", "Bangladesh", "WestIndies", "Zimbabwe" }; Arrays.sort(stringArray, String::compareToIgnoreCase); System.out.println(Arrays.toString(stringArray)); } }Output[Australia, Bangladesh, England, India, Newzealand, SouthAfrica, WestIndies, Zimbabwe]Example - 2@FunctionalInterface interface Operation { public int average(int ... Read More
A lambda expression is similar to a method that has an argument, body, and return type. It can also be called an anonymous function (method without a name). We need to follow some rules while using formal parameters in a lambda expression.If the abstract method of functional interface is a zero-argument method, then the left-hand side of the arrow (->) must use empty parentheses.If the abstract method of functional interface is a one-argument method, then the parentheses are not mandatory.If the abstract method of functional interface is a multiple argument method, then the parentheses are mandatory. The formal parameters are comma-separated and can be in the same order of the ... Read More
Suppose we have an even number of people n that stand around a circle and each person shakes hands with someone else, so that there will be n / 2 handshakes total. We have to find the number of ways these handshakes could occur such that none of the handshakes cross. The answers may be very large so return the answer mod 10^9 + 7.So, if the input is like n = 2, then the output will be 1To solve this, we will follow these steps −m := 10^9 + 7Define an array dp of size (n+1)dp[0] := 1for initialize i := 0, when i
A lambda expression is an anonymous function (nameless function) that has passed as an argument to another function. We need to follow some rules while using the body of a lambda expression.Rules for the body of a lambda expressionThe body of the lambda expression can be either a single expression or more statements.If we are using a single expression as the body of a lambda expression, then no need to enclose the body with curly braces ({}).If we are using one or more statements as the body of a lambda expression, then enclosing them within curly braces({}) can be mandatory.Syntax(parameters) OR () -> {body with statements separated by;} OR Single StatementExampleinterface Message { ... Read More
Suppose we have an integer array called arr, now in one move we can select a palindromic subarray from index i to j where i
Suppose we have one chocolate bar that consists of some chunks. In each chunk it has its own sweetness given by a list called sweetness. If we want to share the chocolate among K friends so we start cutting the chocolate bar into K+1 piece using K cuts, now each piece consists of some consecutive chunks. If we take out the piece with the minimum total sweetness and give the other pieces to our friends. We have to find the maximum total sweetness of the piece we can get by cutting the chocolate bar optimally.So, if the input is like ... Read More
A lambda expression can implement a functional interface by defining an anonymous function that can be passed as an argument to some method.Enables functional programming: All new JVM based languages take advantage of the functional paradigm in their applications, but programmers forced to work with Object-Oriented Programming (OOPS) till lambda expressions came. Hence lambda expressions enable us to write functional code.Readable and concise code: People have started using lambda expressions and reported that it can help to remove a huge number of lines from their code.Easy-to-Use APIs and Libraries: An API designed using lambda expressions can be easier to use and support other API.Enables support for ... Read More
A Stream API is a powerful way to achieve functional programming in Java. It usually works in conjunction with a lambda expression and provides an efficient way to perform data manipulation operations like sort, filter, map, reduce and etc.In the below example, we can sort a collection using Stream API. It provides sorting logic by using the sorted() method of the Comparator interface. If we have two Comparator interface instances and need to do sorting by composite condition (by the first comparator and then by the second comparator), we can use both comparators by invoking the thenComparing() method on the first instance and passing in the second instance.Exampleimport java.util.*; import java.util.stream.*; ... Read More
Suppose we have a string s and another number k; we have to check whether the given string is a K-Palindrome or not.A string is said to be K-Palindrome if it can be transformed into a palindrome by removing at most k characters from it.So, if the input is like s = "abcdeca", k = 2, then the output will be true as by removing 'b' and 'e' characters, it will be palindrome.To solve this, we will follow these steps −Define a function lcs(), this will take s, t, n := size of sadd one blank space before sadd one ... Read More
Suppose we have a list of blocks, if we have blocks[i] = t, this means that the i-th block needs t units of time to be built. A block can only be built by exactly one worker. Single worker can either split into two workers or build a block then go home. These two decisions take some time. The time cost of spliting one worker into two workers is given as a number called split.So, if the input is like blocks = [1, 2], and split = 5, then the output will be 7 as we can split the worker ... Read More