Where is Heap Sort used practically?
MergeSort also has upper bound as O(nLogn) and works better in practice when compared to HeapSort. But MergeSort requires O(n) extra space
HeapSort is not used much in practice, but can be useful in real time (or time bound where QuickSort doesn’t fit) embedded systems where less space is available (MergeSort doesn’t fit). Please refer IntroSort for example
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