// Inserts a word into the trie.
void insert(string s)
{
if (s.empty())
return;
TrieNode* p = root;
int i = 0;
while (i < s.size())
{
TrieNode* tmp = p->findCh(s[i]);
if (nullptr == tmp)
{
p->addChild(s[i]);
++i;
p = p->getLastChild();
}
else
{
++i;
p = tmp;
}
}
p->isAWord(true);
return;
}
// Returns if there is any word in the trie
// that starts with the given prefix.
bool startsWith(string prefix)
{
if (prefix.empty() || " " == prefix)
return true;
TrieNode* p = root;
int i = 0;
while (nullptr != p && i < prefix.size())
{
p = p->findCh(prefix[i++]);
}
if (nullptr == p && i <= prefix.size())
return false;
else if (nullptr != p && i == prefix.size())
return true;
}
// Returns if the word is in the trie.
bool search(string key)
{
if (key.empty() || " " == key)
return true;
TrieNode* p = root;
int i = 0;
while (nullptr != p && i < key.size())
{
p = p->findCh(key[i++]);
}
if (nullptr == p)
return false;
else if (i == key.size() && p->isAWord())
return true;
return false;
}