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Implement Trie (Prefix Tree).cpp
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Implement Trie (Prefix Tree).cpp
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class TrieNode {
public:
vector<TrieNode*> children;
bool isEnd;
char content;
// Initialize your data structure here.
TrieNode() {
content = ' ';
isEnd = false;
};
TrieNode(char ch) {
content = ch;
isEnd = false;
}
};
class Trie {
public:
Trie() {
root = new TrieNode();
}
// Inserts a word into the trie.
void insert(string word) {
if(search(word))
return;
TrieNode* cur = root;
for(int i = 0; i < word.size(); i++) {
TrieNode* pre = cur;
cur = find_children(cur->children, word[i]);
if(cur == nullptr) {
TrieNode* new_child = new TrieNode(word[i]);
pre->children.push_back(new_child);
cur = new_child;
}
}
cur->isEnd = true;
}
// Returns if the word is in the trie.
bool search(string word) {
TrieNode* cur = root;
for(int i = 0; i < word.size(); i++) {
cur = find_children(cur->children, word[i]);
if(cur == nullptr) {
return false;
}
}
return cur->isEnd == true;
}
// Returns if there is any word in the trie
// that starts with the given prefix.
bool startsWith(string prefix) {
TrieNode* cur = root;
for(int i = 0; i < prefix.size(); i++) {
cur = find_children(cur->children, prefix[i]);
if(cur == nullptr) {
return false;
}
}
return true;
}
TrieNode* find_children(vector<TrieNode*> children, char ch) {
for(int i = 0; i < children.size(); i++) {
if(children[i]->content == ch)
return children[i];
}
return nullptr;
}
private:
TrieNode* root;
};
// Your Trie object will be instantiated and called as such:
// Trie trie;
// trie.insert("somestring");
// trie.search("key");