Huffman Coding Using a Heap

Huffman Code Theory

Programming a Huffman Code Using a Heap

Huffman Codes and the Prefix Property

prefix code is a type of code system (typically a variable-length code) distinguished by its possession of the "prefix property", which requires that there is no whole code word in the system that is a prefix (initial segment) of any other code word in the system. - Wikipedia

This property is better explained in the following video: