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May-14 2020 Challenge




Implement Trie (Prifix Tree)
Implement a trie with insert, search, and startsWith methods.

Example:
Trie trie = new Trie();

trie.insert("apple");
trie.search("apple");   // returns true
trie.search("app");     // returns false
trie.startsWith("app"); // returns true
trie.insert("app");   
trie.search("app");     // returns true

Note:
  • You may assume that all inputs are consist of lowercase letters a-z.
  • All inputs are guaranteed to be non-empty strings.

Solution in python:


class Trie(object):
   def __init__(self):
      self.child = {}
   def insert(self, word):
      current = self.child
      for l in word:
         if l not in current:
            current[l] = {}
         current = current[l]
      current['#']=1
   def search(self, word):
      current = self.child
      for l in word:
         if l not in current:
            return False
         current = current[l]
      return '#' in current
   def startsWith(self, prefix):
      current = self.child
      for l in prefix:
         if l not in current:
            return False
         current = current[l]
      return True
ob1 = Trie()
ob1.insert("apple")
print(ob1.search("apple"))
print(ob1.search("app"))
print(ob1.startsWith("app"))
ob1.insert("app")
print(ob1.search("app"))
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