89 lines
1.6 KiB
C++
89 lines
1.6 KiB
C++
/* Heap sort in c++ */
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#include <iostream>
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using namespace std;
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// A function to heapify the array.
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void MaxHeapify(int a[], int i, int n)
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{
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int j, temp;
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temp = a[i];
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j = 2*i;
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while (j <= n)
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{
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if (j < n && a[j+1] > a[j])
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j = j+1;
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// Break if parent value is already greater than child value.
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if (temp > a[j])
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break;
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// Switching value with the parent node if temp < a[j].
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else if (temp <= a[j])
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{
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a[j/2] = a[j];
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j = 2*j;
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}
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}
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a[j/2] = temp;
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return;
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}
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void HeapSort(int a[], int n)
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{
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int i, temp;
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for (i = n; i >= 2; i--)
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{
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// Storing maximum value at the end.
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temp = a[i];
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a[i] = a[1];
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a[1] = temp;
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// Building max heap of remaining element.
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MaxHeapify(a, 1, i - 1);
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}
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}
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void Build_MaxHeap(int a[], int n)
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{
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int i;
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for(i = n/2; i >= 1; i--)
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MaxHeapify(a, i, n);
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}
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int main()
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{
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int n, i;
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cout<<"\nEnter the number of data element to be sorted: ";
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cin>>n;
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n++;
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int* arr = new int[n];
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for(i = 1; i < n; i++)
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{
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cout<<"Enter element "<<i<<": ";
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cin>>arr[i];
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}
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// Building max heap.
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Build_MaxHeap(arr, n-1);
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HeapSort(arr, n-1);
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// Printing the sorted data.
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cout<<"\nSorted Data ";
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for (i = 1; i < n; i++)
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cout<<"->"<<arr[i];
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cout<<"\nTime Complexity: Best case = Avg case = Worst case = O(n logn)";
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return 0;
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}
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/* Runtime test case:-
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Enter the number of data elements to be sorted: 7
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Enter element 1: 10
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Enter element 2: 8
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Enter element 3: 12
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Enter element 4: 1
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Enter element 5: 2
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Enter element 6: 0
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Enter element 7: 15
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Sorted Data ->0->1->2->8->10->12->15
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Time Complexity: Best case = Avg case = Worst case = O(n logn) */
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