# Question

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

class Node(object):
def __init__(self):
self.isEnd = False
self.next = [None] * 26

class Trie(object):

def __init__(self):
"""
"""
self.root = Node()

def insert(self, word):
"""
Inserts a word into the trie.
:type word: str
:rtype: void
"""
node = self.root
for c in word:
idx = self._index(c)
if node.next[idx] is None:
node.next[idx] = Node()
node = node.next[idx]
node.isEnd = True

def search(self, word):
"""
Returns if the word is in the trie.
:type word: str
:rtype: bool
"""
node = self.root
for c in word:
idx = self._index(c)
if node.next[idx] is None:
return False
node = node.next[idx]
return node.isEnd

def startsWith(self, prefix):
"""
Returns if there is any word in the trie that starts with the given prefix.
:type prefix: str
:rtype: bool
"""
node = self.root
for c in prefix:
idx = self._index(c)
if node.next[idx] is None:
return False
node = node.next[idx]
return True

def _index(self, c):
return ord(c) - ord('a')

# Your Trie object will be instantiated and called as such:
# obj = Trie()
# obj.insert(word)
# param_2 = obj.search(word)
# param_3 = obj.startsWith(prefix)