Data structure algorithms in Java

Category : Java | Sub Category : Java Programs from Coding Interviews | By Prasad Bonam Last updated: 2023-07-10 04:35:48 Viewed : 359

Here are some commonly used data structure algorithms in Java with code examples:

1. Binary Search: Binary search is an algorithm for finding a specific target value within a sorted array. It compares the target value with the middle element of the array and recursively narrows down the search range.

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

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

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

    return -1; // Target not found
}

2. Bubble Sort: Bubble sort is a simple comparison-based sorting algorithm. It repeatedly swaps adjacent elements if they are in the wrong order until the entire array is sorted.

javaCopy code
public static void bubbleSort(int[] arr) {
    int n = arr.length;
    for (int i = 0; i < n - 1; i++) {
        for (int j = 0; j < n - i - 1; j++) {
            if (arr[j] > arr[j + 1]) {
                // Swap arr[j] and arr[j+1]
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

3. Depth-First Search (DFS): DFS is an algorithm for traversing or searching tree or graph data structures. It explores as far as possible along each branch before backtracking.

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public class Graph {
    private int vertices;
    private LinkedList<Integer>[] adjacencyList;

    // ...

    public void DFS(int startVertex) {
        boolean[] visited = new boolean[vertices];
        DFSUtil(startVertex, visited);
    }

    private void DFSUtil(int vertex, boolean[] visited) {
        visited[vertex] = true;
        System.out.print(vertex + " ");

        for (Integer neighbor : adjacencyList[vertex]) {
            if (!visited[neighbor]) {
                DFSUtil(neighbor, visited);
            }
        }
    }
}

These are just a few examples of data structure algorithms in Java. Java provides a rich set of libraries and APIs for various data structures and algorithms. You can explore more algorithms such as sorting (e.g., QuickSort, MergeSort), graph algorithms (e.g., Breadth-First Search, Dijkstras algorithm), and more based on your specific requirements and use cases.