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Merge branch 'main' into heap-sort
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‎C/algorithms/sorting/merge_sort.c‎

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/*
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* Algorithm: Merge Sort
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* Description: Divide-and-conquer sorting algorithm that divides array into halves,
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* sorts them separately, and merges them back together
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* Time Complexity: O(n log n) for all cases
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* Space Complexity: O(n) for temporary arrays
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* Author: Abhijit
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* Date: October 2025
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* Hacktoberfest 2025
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*/
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#include <stdio.h>
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#include <stdlib.h>
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/**
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* Merges two subarrays of arr[]
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* First subarray is arr[left..mid]
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* Second subarray is arr[mid+1..right]
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*/
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void merge(int arr[], int left, int mid, int right) {
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int i, j, k;
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int n1 = mid - left + 1;
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int n2 = right - mid;
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// Create temporary arrays
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int *leftArray = (int*)malloc(n1 * sizeof(int));
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int *rightArray = (int*)malloc(n2 * sizeof(int));
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// Copy data to temporary arrays
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for (i = 0; i < n1; i++)
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leftArray[i] = arr[left + i];
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for (j = 0; j < n2; j++)
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rightArray[j] = arr[mid + 1 + j];
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// Merge the temporary arrays back into arr[left..right]
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i = 0; // Initial index of first subarray
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j = 0; // Initial index of second subarray
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k = left; // Initial index of merged subarray
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while (i < n1 && j < n2) {
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if (leftArray[i] <= rightArray[j]) {
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arr[k] = leftArray[i];
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i++;
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} else {
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arr[k] = rightArray[j];
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j++;
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}
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k++;
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}
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// Copy the remaining elements of leftArray[], if any
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while (i < n1) {
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arr[k] = leftArray[i];
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i++;
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k++;
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}
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// Copy the remaining elements of rightArray[], if any
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while (j < n2) {
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arr[k] = rightArray[j];
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j++;
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k++;
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}
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// Free the temporary arrays
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free(leftArray);
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free(rightArray);
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}
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/**
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* Main function that sorts arr[left..right] using merge sort
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*/
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void mergeSort(int arr[], int left, int right) {
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if (left < right) {
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// Find the middle point to divide the array into two halves
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int mid = left + (right - left) / 2;
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// Sort first and second halves
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mergeSort(arr, left, mid);
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mergeSort(arr, mid + 1, right);
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// Merge the sorted halves
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merge(arr, left, mid, right);
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}
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}
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/**
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* Utility function to print array elements
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*/
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void printArray(int arr[], int n) {
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for (int i = 0; i < n; i++) {
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printf("%d ", arr[i]);
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}
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printf("\n");
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}
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int main() {
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int n;
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// Prompt the user for the number of elements
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printf("Enter the number of elements: ");
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scanf("%d", &n);
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if (n <= 0) {
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printf("Invalid input! Number of elements must be positive.\n");
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return 1;
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}
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int arr[n]; // Declare an array of size n
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// Read the elements from the user
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printf("Enter %d numbers: ", n);
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for (int i = 0; i < n; i++) {
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scanf("%d", &arr[i]);
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}
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printf("\nOriginal array: ");
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printArray(arr, n);
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mergeSort(arr, 0, n - 1);
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printf("Sorted array: ");
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printArray(arr, n);
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printf("\nAlgorithm Information:\n");
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printf("- Time Complexity: O(n log n) for all cases\n");
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printf("- Space Complexity: O(n) for temporary arrays\n");
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printf("- Stable sorting algorithm\n");
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printf("- Divide-and-conquer approach\n");
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return 0;
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}

‎HALL_OF_FAME.md‎

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@@ -339,7 +339,7 @@ Welcome to the **Hall of Fame**! This page celebrates all the amazing contributo
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| Metric | Count | Growth |
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|--------|-------|--------|
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| 👥 **Total Contributors** | 77+ Amazing Developers | 📈 +Growing Daily |
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| 👥 **Total Contributors** | 81+ Amazing Developers | 📈 +Growing Daily |
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| 📝 **Total Commits** | 200+ Quality Commits | 📈 +Active Development |
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| 🔥 **Algorithms Implemented** | 100+ Implementations | 📈 +Weekly Additions |
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| 🌍 **Languages Supported** | 4 (C, C++, Java, Python) | 📈 +Expanding |
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#### 🙏 **Special Thanks to All Our 2024 Contributors**
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We extend our heartfelt gratitude to all **77+ contributors** who made this repository possible in 2024:
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We extend our heartfelt gratitude to all **81+ contributors** who made this repository possible in 2024:
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**🏆 Top Contributors (5+ commits):**
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- [@Pradeepsingh61](https://github.com/Pradeepsingh61) - 130 contributions 👑 **Project Founder**

‎Java/algorithms/sorting/HeapSort.java‎

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import java.util.Arrays;
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public class HeapSort {
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static void heapify(int arr[], int n, int i) {
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int largest = i;
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int left = 2 * i + 1;
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int right = 2 * i + 2;
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if (left < n && arr[left] > arr[largest])
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largest = left;
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if (right < n && arr[right] > arr[largest])
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largest = right;
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if (largest != i) {
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int temp = arr[i];
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arr[i] = arr[largest];
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arr[largest] = temp;
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heapify(arr, n, largest);
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}
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}
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static void heapSort(int arr[]) {
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int n = arr.length;
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for (int i = n / 2 - 1; i >= 0; i--)
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heapify(arr, n, i);
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for (int i = n - 1; i >= 0; i--) {
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int temp = arr[0];
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arr[0] = arr[i];
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arr[i] = temp;
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heapify(arr, i, 0);
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}
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}
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public static void main(String[] args) {
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int arr[] = {12, 11, 13, 5, 6, 7};
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System.out.println("Original array: " + Arrays.toString(arr));
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heapSort(arr);
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System.out.println("Sorted array: " + Arrays.toString(arr));
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}
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}

‎Python/algorithms/sorting/heap_sort.py‎

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"""
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Heap Sort Algorithm
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Time Complexity: O(n log n) in all cases
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Space Complexity: O(1) - sorts in place
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Author: Karanjot Singh
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Date: October 2025
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Hacktoberfest 2025
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"""
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def heapify(arr, n, i):
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"""
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Heapify subtree rooted at index i
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Args:
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arr: Array to heapify
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n: Size of heap
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i: Root index of subtree
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"""
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largest = i
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l = 2 * i + 1
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r = 2 * i + 2
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left = 2 * i + 1
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right = 2 * i + 2
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# Check if left child exists and is greater than root
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if left < n and arr[left] > arr[largest]:
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largest = left
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if l < n and arr[l] > arr[largest]:
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largest = l
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if r < n and arr[r] > arr[largest]:
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largest = r
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# Check if right child exists and is greater than largest so far
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if right < n and arr[right] > arr[largest]:
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largest = right
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# If largest is not root, swap and continue heapifying
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if largest != i:
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arr[i], arr[largest] = arr[largest], arr[i]
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heapify(arr, n, largest)
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def heapSort(arr):
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def heap_sort(arr):
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"""
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Heap sort implementation
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Steps:
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1. Build max heap from array
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2. Extract elements one by one from heap
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3. Place extracted element at the end
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Args:
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arr: List to sort (modified in place)
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"""
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n = len(arr)
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# Build max heap
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# Start from last non-leaf node and heapify each node
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for i in range(n // 2 - 1, -1, -1):
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heapify(arr, n, i)
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# Extract elements from heap one by one
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for i in range(n - 1, 0, -1):
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# Move current root to end
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arr[0], arr[i] = arr[i], arr[0]
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# Heapify the reduced heap
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heapify(arr, i, 0)
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# Taking user input
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input_str = input("Enter numbers separated by space: ")
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arr = list(map(int, input_str.split()))
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heapSort(arr)
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def heap_sort_copy(arr):
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"""
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Heap sort that returns sorted copy
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Args:
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arr: List to sort
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Returns:
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Sorted copy of the list
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"""
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arr_copy = arr.copy()
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heap_sort(arr_copy)
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return arr_copy
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# Test cases
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if __name__ == "__main__":
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print("=== Heap Sort Algorithm ===\n")
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# Test case 1: Random array
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test1 = [12, 11, 13, 5, 6, 7]
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print(f"Original array: {test1}")
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sorted1 = heap_sort_copy(test1)
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print(f"Sorted array: {sorted1}")
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# Test case 2: Already sorted
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test2 = [1, 2, 3, 4, 5]
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print(f"\nOriginal array: {test2}")
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sorted2 = heap_sort_copy(test2)
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print(f"Sorted array: {sorted2}")
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# Test case 3: Reverse sorted
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test3 = [10, 8, 6, 4, 2]
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print(f"\nOriginal array: {test3}")
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sorted3 = heap_sort_copy(test3)
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print(f"Sorted array: {sorted3}")
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# Test case 4: Array with duplicates
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test4 = [4, 10, 3, 5, 1, 3, 10]
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print(f"\nOriginal array: {test4}")
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sorted4 = heap_sort_copy(test4)
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print(f"Sorted array: {sorted4}")
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# Test case 5: Large array
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test5 = [64, 34, 25, 12, 22, 11, 90, 88, 45, 50, 23, 36]
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print(f"\nOriginal array: {test5}")
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sorted5 = heap_sort_copy(test5)
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print(f"Sorted array: {sorted5}")
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# Test case 6: Single element
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test6 = [42]
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print(f"\nOriginal array: {test6}")
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sorted6 = heap_sort_copy(test6)
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print(f"Sorted array: {sorted6}")
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print("Sorted array is")
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for i in arr:
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print(i, end=' ')
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print("\n✅ All test cases completed!")

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