-
Notifications
You must be signed in to change notification settings - Fork 0
/
208. Implement Trie - Recursive.cpp
59 lines (53 loc) · 1.46 KB
/
208. Implement Trie - Recursive.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
class TrieNode {
public:
// Initialize your data structure here.
TrieNode() {
isWord = false;
next.resize(26, NULL);
}
bool isWord;
vector<TrieNode*> next;
};
class Trie {
public:
Trie() {
root = new TrieNode();
}
// Inserts a word into the trie.
void insert(string word) {
insert(root, 0, word);
}
// Returns if the word is in the trie.
bool search(string word) {
TrieNode *res = search(root, 0, word);
return res != NULL && res->isWord;
}
// Returns if there is any word in the trie
// that starts with the given prefix.
bool startsWith(string prefix) {
TrieNode *res = search(root, 0, prefix);
return res != NULL;
}
private:
TrieNode* root;
TrieNode* insert(TrieNode* root, int depth, const string &word){
if(!root) root = new TrieNode();
if(depth == word.length()){
root->isWord = true;
return root;
}
int c = word[depth++] - 'a';
root->next[c] = insert(root->next[c], depth, word);
return root;
}
TrieNode* search(TrieNode* root, int depth, const string &word){
if(!root) return NULL;
if(depth == word.length()) return root;
int c = word[depth++] - 'a';
return search(root->next[c], depth, word);
}
};
// Your Trie object will be instantiated and called as such:
// Trie trie;
// trie.insert("somestring");
// trie.search("key");