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Author: DeveloperNA

MaxHeap/maxHeap.cpp

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+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+class EmptyHeapException : exception{};
+
+class MaxHeap
+{
+    private:
+        vector<int> arr;
+    
+    public:
+        int top;
+        MaxHeap();
+        MaxHeap(int data);
+
+        void push(int data);
+        void pop() throw(EmptyHeapException);
+
+        bool empty();
+        int getMaxChildIndex(int, int);
+        void printHeap();
+};
+
+MaxHeap::MaxHeap()
+{
+    this->top = -999;
+    this->arr.push_back(-999);
+}   
+
+MaxHeap::MaxHeap(int data)
+{
+    this->arr.push_back(0);
+    this->arr.push_back(data);
+    this->top = data;
+}
+
+bool MaxHeap::empty()
+{
+    if(this->arr.size() == 1)
+        return true;
+    else
+        return false;
+}
+
+void MaxHeap::push(int data)
+{
+    this->arr.push_back(data);
+    int i, parent;
+    i=arr.size()-1;
+    parent = i/2;
+    
+    while(i>1 && arr[parent] < arr[i]){
+        
+        swap(arr[parent], arr[i]);
+        i = parent;
+        parent = i/2;
+    }
+ 
+    this->top = arr[1];
+}
+
+void MaxHeap::pop() throw(EmptyHeapException)
+{   
+    int i, parentIndex, leftIndex, rightIndex, maxChildIndex;
+
+    try{
+        if(this->empty()){
+            throw EmptyHeapException();
+        }
+
+        this->arr[1] = this->arr[this->arr.size()-1];
+        this->arr.pop_back();
+
+        parentIndex = 1;
+        leftIndex = (2*parentIndex > this->arr.size())? 0 : 2*parentIndex;
+        rightIndex = (2*parentIndex +1>this->arr.size())? 0 : 2*parentIndex+1;
+
+        maxChildIndex = getMaxChildIndex(leftIndex, rightIndex);
+
+        while(this->arr[parentIndex] < this->arr[maxChildIndex] && (leftIndex!=0 || rightIndex!=0)){
+            
+            swap(this->arr[parentIndex], this->arr[maxChildIndex]);
+            
+            parentIndex = maxChildIndex;
+            leftIndex = (2*parentIndex > this->arr.size())? 0 : 2*parentIndex;
+            rightIndex = (2*parentIndex+1 > this->arr.size())? 0 : 2*parentIndex+1;
+
+            maxChildIndex = getMaxChildIndex(leftIndex, rightIndex);
+        }
+        this->top = this->arr[1];
+    }   
+    catch(EmptyHeapException e){
+        cout << "\n\t\t/////Deletion cannot be perfomed on empty heap/////" << endl;
+    }
+}
+
+int MaxHeap::getMaxChildIndex(int left, int right)
+{
+    return (this->arr[left] > this->arr[right])? left: right;
+}
+
+void swap(int *p, int *q)
+{
+    int temp = *p;
+    *p = *q;
+    *q = temp;
+}
+
+void MaxHeap::printHeap()
+{
+    cout << endl;
+    for(int i=1; i<this->arr.size(); i++){
+        cout << this->arr[i] << " ";
+    }
+    cout << endl;
+}
+
+int main()
+{
+    MaxHeap myHeap;
+    myHeap.push(10);
+    myHeap.push(40);
+    myHeap.push(20);
+    myHeap.push(30);
+    myHeap.printHeap();
+    myHeap.push(50);
+    myHeap.push(32);
+    myHeap.push(70);
+
+    myHeap.printHeap();
+
+    cout << endl <<  myHeap.top << endl;
+
+    myHeap.pop();
+
+    cout << myHeap.top << endl;
+    myHeap.pop();
+    cout << myHeap.top << endl;
+    myHeap.pop();
+    cout << myHeap.top << endl;
+    myHeap.pop();
+    cout << myHeap.top << endl;
+    myHeap.pop();
+    cout << myHeap.top << endl;
+    myHeap.pop();
+    cout << myHeap.top << endl;
+    myHeap.pop();
+    myHeap.pop();
+
+    return 0;
+}