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tries/README.md

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 * tries, also called prefix tree, are a variant of n-ary tree in which characters are stored in each node.
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 * each trie node represents a string (a prefix) and each path down the tree represents a word. note that not all the strings represented by trie nodes are meaningful.
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 * the root is associated with the empty string.
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 * the * nodes (null nodes) are often used to indicate complete words (usually represented by a special type of child) or a boolean flag that terminates the parent node.
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 * a node can have anywhere from 1 through alphabet_size + 1 child.
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 * can be used to store the entire english language for quick prefix lookup (O(k), where k is the length of the string). they are also widely used on autocompletes, spell checkers, and ip routing (longest prefix matching).
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 * tries structures can be represented by arrays and maps or trees.
 
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 ### insertion
 
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 ### search
 
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