The most important thing in quick sort is partition, once you understand the process of partition you can understand the quick sort.
Quick sort uses divide & conquer method.
There are three important procedures in heap sorting.
I learnt insertion sort, I think the most important part of it is:
A[i+1] = A[i]
This is used to move node, e.g. array node. And the stop condition is:
i<0 || a[i] <= key
The main conception of merge sort is divide and conquer.
Division aims at dividing the array into separated one using binary method.