Tag: Programming

Categories
Algorithms Java

Implementing Binary Search Algorithm for Efficient Searching of Sorted Arrays

white and black jigsaw puzzle
Reading Time: 2 mins

Introduction

Binary search is a search algorithm that works on sorted data. It operates by repeatedly dividing the search interval in half until the target value is found or the interval is empty. It’s a very efficient algorithm, with a runtime complexity of O(log n), where n is the number of elements in the array.

In this article, we’ll walk through how to implement binary search in Java to search for an integer in a sorted array.

Implementation

Let’s start by writing a method that performs a binary search. The method takes two arguments: an array of integers nums and an integer target that we’re searching for. The method returns the index of the target if it exists in the array, or -1 if it doesn’t.

public static int binarySearch(int[] nums, int target) {
    int left = 0;
    int right = nums.length - 1;

    while (left <= right) {
        int mid = left + (right - left) / 2;

        if (nums[mid] == target) {
            return mid;
        } else if (nums[mid] < target) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }

    return -1;
}

Here’s how the method works:

  • We start by setting left to the first index of the array, and right to the last index of the array.
  • We use a while loop to keep searching until the search interval is empty (left is greater than right), or we’ve found the target value.
  • In each iteration of the loop, we compute the midpoint of the search interval using the formula mid = left + (right - left) / 2. This avoids integer overflow errors that can occur if we use the simpler formula (left + right) / 2.
  • If the value at nums[mid] is equal to the target, we’ve found it, so we return mid.
  • If the value at nums[mid] is less than the target, we need to search the right half of the search interval, so we update left = mid + 1.
  • If the value at nums[mid] is greater than the target, we need to search the left half of the search interval, so we update right = mid - 1.

Example

Let’s look at an example of how to use the binarySearch method. Suppose we have the following array of integers:

int[] nums = {1, 3, 5, 7, 9};

We want to search for the value 5 in the array. We can call the binarySearch method like this:

int index = binarySearch(nums, 5);

The index variable will contain the value 2, which is the index of the value 5 in the array.

Conclusion

Binary search is a very efficient algorithm for searching sorted data. In this article, we’ve seen how to implement binary search in Java to search for an integer in a sorted array. We used a while loop to repeatedly divide the search interval in half, and we updated the search interval based on whether the target value was greater than or less than the midpoint value. By using this algorithm, we can search a large array in logarithmic time, which is much faster than linear search.

Categories
Courses JavaScript - Beginner to Advanced

JavaScript Variables and Data Types

Photo by Lukas on Pexels.com
Reading Time: 3 mins

JavaScript is a popular programming language used for building web applications. Understanding variables and data types are essential for anyone working with JavaScript. This article will discuss variables and data types in JavaScript, including relevant code examples.

Variables

In JavaScript, variables are used to store data values. The var keyword is used to declare variables in JavaScript. Here is an example of how to declare a variable:

var age = 25;

In this example, we declared a variable called age and assigned it the value 25. Once a variable has been declared, it can be used throughout the code.

Naming Conventions

When naming variables in JavaScript, it is important to follow naming conventions. Variables in JavaScript are case-sensitive and can include letters, digits, underscores, and dollar signs. They cannot start with a digit. It is also important to choose a descriptive name for the variable that reflects its purpose. Here are some examples of valid variable names in JavaScript:

var name = "John";
var age = 25;
var _name = "John";
var $name = "John";

Variable Scope

In JavaScript, variables have function scope. This means that a variable declared inside a function is only accessible within that function. Here is an example:

function myFunction() {
  var x = 10;
  console.log(x);
}
myFunction(); // Output: 10
console.log(x); // Output: ReferenceError: x is not defined

In this example, the variable x is declared inside the function myFunction. It is not accessible outside of the function.

Data Types

JavaScript has several data types, including strings, numbers, booleans, null, undefined, and objects.

Strings

Strings are used to represent text in JavaScript. They are enclosed in quotes, either single or double. Here are some examples:

var firstName = "John";
var lastName = 'Doe';
var message = "Hello, world!";

Numbers

Numbers are used to representing numeric data in JavaScript. They can be integers or decimals. Here are some examples:

var age = 25;
var pi = 3.14;

Booleans

Booleans are used to represent true/false values in JavaScript. They can only have two values: true or false. Here are some examples:

var isStudent = true;
var isWorking = false;

Null and Undefined

null and undefined are used to represent empty or non-existent values in JavaScript. They are often used interchangeably, but there is a subtle difference. null is an assignment value that represents no value or an empty value, while undefined is a variable that has been declared but has not been assigned a value. Here are some examples:

var firstName = null;
var lastName; // undefined

Objects

Objects are used to represent complex data structures in JavaScript. They are collections of properties, where each property consists of a key-value pair. Here is an example:

var person = {
  firstName: "John",
  lastName: "Doe",
  age: 25,
  isStudent: true
};

In this example, we created an object called person with four properties: firstName, lastName, age, and isStudent. The properties are accessed using dot notation or bracket notation.

Conclusion

In this article, we discussed variables and data types in JavaScript. Variables are used to store data values in JavaScript, and they are declared using the var keyword. It is important to follow naming conventions and choose descriptive names for variables. JavaScript has several data types: strings, numbers, booleans, null, undefined, and objects. Understanding variables and data types are crucial for building robust JavaScript applications.

In summary, JavaScript is a versatile language with many applications, and understanding the basics of variables and data types is essential for building functional programs. With the code examples provided in this article, you should now have a solid understanding of how to declare and use variables, as well as the different data types available in JavaScript. By following the best practices discussed here, you can write efficient and effective JavaScript code that will help you achieve your goals.

Exit mobile version

Terms and Conditions - Privacy Policy