Create main.cpp

Author: JawadSher

19 - Heap Data Structure Problems/01 - Example/main.cpp

@@ -0,0 +1,189 @@
+#include <iostream>
+#include <algorithm>  // For STL heap functions
+#include <vector>
+using namespace std;
+
+class Heap {
+public:
+    int arr[100];
+    int size;
+
+    Heap() {
+        arr[0] = -1; // Initialize array with -1 at index 0 (1-based indexing)
+        size = 0;    // Initial size of heap is 0
+    }
+
+    // Insert a new element into the heap
+    void insert(int value) {
+        size++;
+        int index = size;
+        arr[index] = value;
+
+        // Heapify up to maintain max heap property
+        while (index > 1) {
+            int parent = index / 2;
+            if (arr[parent] < arr[index]) {
+                swap(arr[parent], arr[index]);
+                index = parent;  // Move up to parent
+            } else {
+                return;
+            }
+        }
+    }
+
+    // Delete the root element from the heap
+    void deleteFromHeap() {
+        if (size == 0) {
+            cout << "Nothing to delete" << endl;
+            return;
+        }
+
+        // Replace root with the last element
+        arr[1] = arr[size];
+        size--;
+
+        // Heapify down to maintain max heap property
+        int i = 1;
+        while (i <= size) {
+            int leftIndex = 2 * i;
+            int rightIndex = 2 * i + 1;
+            int largest = i;
+
+            if (leftIndex <= size && arr[largest] < arr[leftIndex]) {
+                largest = leftIndex;
+            }
+            if (rightIndex <= size && arr[largest] < arr[rightIndex]) {
+                largest = rightIndex;
+            }
+            if (largest != i) {
+                swap(arr[i], arr[largest]);
+                i = largest;
+            } else {
+                return;
+            }
+        }
+    }
+
+    // Print the heap
+    void print() {
+        for (int i = 1; i <= size; i++) {
+            cout << arr[i] << " ";
+        }
+        cout << endl;
+    }
+};
+
+// Heapify for max heap
+void max_heapify(int arr[], int n, int i) {
+    int largest = i;
+    int left = 2 * i;
+    int right = 2 * i + 1;
+
+    if (left <= n && arr[largest] < arr[left]) largest = left;
+    if (right <= n && arr[largest] < arr[right]) largest = right;
+
+    if (largest != i) {
+        swap(arr[largest], arr[i]);
+        max_heapify(arr, n, largest);
+    }
+}
+
+// Heapify for min heap
+void min_heapify(int arr[], int n, int i) {
+    int smallest = i;
+    int left = 2 * i + 1;
+    int right = 2 * i + 2;
+
+    if (left < n && arr[smallest] > arr[left]) smallest = left;
+    if (right < n && arr[smallest] > arr[right]) smallest = right;
+
+    if (smallest != i) {
+        swap(arr[smallest], arr[i]);
+        min_heapify(arr, n, smallest);
+    }
+}
+
+// Sort a max heap (ascending order)
+void maxHeapSort(int arr[], int n) {
+    // Build a max heap
+    for (int i = n / 2; i > 0; i--) {
+        max_heapify(arr, n, i);
+    }
+
+    // Sort
+    for (int i = n; i > 1; i--) {
+        swap(arr[1], arr[i]);
+        max_heapify(arr, i - 1, 1);
+    }
+}
+
+// Sort a min heap (descending order)
+void minHeapSort(int arr[], int n) {
+    for (int i = n / 2 - 1; i >= 0; i--) {
+        min_heapify(arr, n, i);
+    }
+
+    for (int i = n - 1; i > 0; i--) {
+        swap(arr[0], arr[i]);
+        min_heapify(arr, i, 0);
+    }
+}
+
+int main() {
+    Heap h;
+    h.insert(50);
+    h.insert(55);
+    h.insert(53);
+    h.insert(52);
+    h.insert(54);
+
+    cout << "Max Heap after insertions:" << endl;
+    h.print();
+    h.deleteFromHeap();
+    cout << "Max Heap after deletion:" << endl;
+    h.print();
+
+    cout << endl;
+
+    // Max Heap Creation using array
+    int max_arr[6] = {-1, 54, 53, 55, 52, 50};
+    int n = 5;
+    for (int i = n / 2; i > 0; i--) {
+        max_heapify(max_arr, n, i);
+    }
+
+    cout << "Heapify array - Max Heap" << endl;
+    for (int i = 1; i <= n; i++) {
+        cout << max_arr[i] << " ";
+    }
+    cout << endl;
+
+    maxHeapSort(max_arr, n);
+    cout << "Printing max sorted heap (Ascending Order)" << endl;
+    for (int i = 1; i <= n; i++) {
+        cout << max_arr[i] << " ";
+    }
+    cout << endl << endl;
+
+    // Min Heap Creation using array
+    int min_arr[5] = {54, 53, 55, 52, 50};
+    int m = 5;
+    for (int i = m / 2 - 1; i >= 0; i--) {
+        min_heapify(min_arr, m, i);
+    }
+
+    cout << "Heapify array - Min Heap" << endl;
+    for (int i = 0; i < m; i++) {
+        cout << min_arr[i] << " ";
+    }
+    cout << endl;
+
+    minHeapSort(min_arr, m);
+    cout << "Printing min sorted heap (Descending Order)" << endl;
+    for (int i = 0; i < m; i++) {
+        cout << min_arr[i] << " ";
+    }
+    cout << endl;
+
+    return 0;
+}