A Heap is a special Tree-based data structure in which the tree is a complete binary tree. Generally, Heaps can be of two types:

Max-Heap: In a Max-Heap the key present at the root node must be greatest among the keys present at all of it’s children. 

Min-Heap: In a Min-Heap the key present at the root node must be minimum among the keys present at all of it’s children. 
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A linked list is a linear data structure, in which the elements are not stored at contiguous memory locations. The elements in a linked list are linked using pointers. This is how a linked list is pictorially represented.

An algorithm is a set of instructions for solving a problem or accomplishing a task. One common example of an algorithm is a recipe, which consists of specific instructions for preparing a dish or meal. Every computerized device uses algorithms to perform its functions in the form of hardware- or software-based routines.