Merge pull request #1513 from Korra15/heapsort-algorithm

Added heap sort algorithm implemented in c++ #1500

Author: keshavsingh3197

CPP/SortingTechniques/HeapSort.cpp

@@ -0,0 +1,81 @@
+#include <iostream>
+using namespace std;
+class heap1{
+public:
+	void accept();
+	void MAX_HEAPIFY(int a[],int,int);
+	void BUILD_MAX_HEAP(int a[],int);
+	void HEAPSORT(int a[],int);
+	void display(int a[],int );
+};
+void heap1 :: MAX_HEAPIFY(int a[], int i, int n)
+{
+    int l,r,largest,loc;
+    l=2*i;
+    r=(2*i+1);
+    if((l<=n)&&a[l]>a[i])
+       largest=l;
+    else
+       largest=i;
+    if((r<=n)&&(a[r]>a[largest]))
+       largest=r;
+    if(largest!=i)
+    {
+         loc=a[i];
+         a[i]=a[largest];
+         a[largest]=loc;
+         MAX_HEAPIFY(a, largest,n);
+    }
+}
+void heap1 :: BUILD_MAX_HEAP(int a[], int n)
+{
+    for(int k = n/2; k >= 1; k--)
+    {
+        MAX_HEAPIFY(a, k, n);
+    }
+}
+void heap1 :: HEAPSORT(int a[], int n)
+{
+
+    BUILD_MAX_HEAP(a,n);
+    int i, temp;
+    for (i = n; i >= 2; i--)
+    {
+        temp = a[i];
+        a[i] = a[1];
+        a[1] = temp;
+        MAX_HEAPIFY(a, 1, i - 1);
+    }
+}
+
+void heap1::accept(){
+	int n;
+	    cout<<"Enter the number of students"<<endl;
+	    cin>>n;
+	    int a[n];
+	    cout<<"Enter the marks of the students "<<endl;
+	    for (int i = 1; i <= n; i++)
+	    {
+	        cin>>a[i];
+	    }
+	    HEAPSORT(a, n);
+	    display(a,n);
+}
+void heap1::display(int a[],int n){
+
+      cout<<":::::::SORTED MARKS::::::"<<endl;
+
+	    for (int i = 1; i <= n; i++)
+	    {
+	        cout<<a[i]<<endl;
+	    }
+	cout<<"Minimum marks obtained are:"<<a[1];
+	cout<<"\nMaximum marks obtained are:"<<a[n];
+
+}
+int main()
+{
+   	heap1 h;
+	h.accept();
+	return 0;
+}