Random Search Algorithm in Java: Introduction, How It Works, Example

The Random Search algorithm, also known as Monte Carlo search, is a searching method based on randomness. Instead of sequentially checking each element in a data array, this algorithm randomly selects a number of elements to examine. This approach saves time and resources compared to sequential searching.

How It Works

  1. Step 1: Begin with the data array you want to search.

  2. Step 2: Randomly select a certain number of elements to examine.

  3. Step 3: Check the selected elements to see if they match the search condition.

  4. Step 4: If a matching element is found, return the result; if not, return to Step 2.

  5. Step 5: Continue the process until a match is found or the maximum number of attempts is reached.

Advantages and Disadvantages


  • Resource-Efficient: Saves time and memory, especially for large data arrays.
  • Randomness: Not easily predictable, suitable for situations that require randomness.


  • No Guarantee of Success: There is no assurance that the algorithm will find the desired result.
  • May Take a Long Time: In the worst case, the algorithm can take longer than sequential search.

Example and Explanation

Consider the following example of using the Random Search Algorithm to find an integer in an array:

import java.util.Random;

public class RandomSearchExample {
    static int randomSearch(int[] arr, int target) {
        Random rand = new Random();
        int maxAttempts = arr.length; // Maximum number of attempts
        for (int i = 0; i < maxAttempts; i++) {
            int randomIndex = rand.nextInt(arr.length); // Randomly select an index
            if (arr[randomIndex] == target) {
                return randomIndex; // Return the index if found
        return -1; // Return -1 if not found

    public static void main(String[] args) {
        int[] numbers = {1, 5, 9, 3, 7};
        int target = 3;
        int result = randomSearch(numbers, target);
        if (result != -1) {
            System.out.println("Number " + target + " found at index " + result);
        } else {
            System.out.println("Number " + target + " not found in the array.");

In this example, we use the Random Search Algorithm to find an integer in an array. We iterate through the array, randomly select an index, and check if the element at that index matches the target number. If found, we return the index; if not, we continue until the maximum number of attempts is reached.