Data Stucture: Trie (C++)

[t3bol90]

Submission Checklist

• [x] Your pull request targets the master branch of the repository.
• [x] You have only one commit (if not, squash them into one commit).
• [x] You have read the Contributing guidelines and your changes follow them.

Type of Change

• [ ] Bug fix
• [x] New implementation

PR Description

I'm adding new Data Structure - Trie. "In computer science, a trie, also called digital tree or prefix tree, is a kind of search tree—an ordered tree data structure used to store a dynamic set or associative array where the keys are usually strings. Unlike a binary search tree, no node in the tree stores the key associated with that node; instead, its position in the tree defines the key with which it is associated. All the descendants of a node have a common prefix of the string associated with that node, and the root is associated with the empty string. Keys tend to be associated with leaves, though some inner nodes may correspond to keys of interest." - by Wikipedia.

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