-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy path208. Implement Trie(Prefix Tree).cpp
98 lines (76 loc) · 1.91 KB
/
208. Implement Trie(Prefix Tree).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
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
class TrieNode {
public:
char ch;
bool isend;
vector<TrieNode *> children;
// Initialize your data structure here.
TrieNode(): ch(' '),isend(false) {};
TrieNode(char c) : ch(c), isend(false) {};
TrieNode *fchild(char c) {
if (!children.empty()) {
for(auto child: children) {
if(child->ch == c)
return child;
}
}
return NULL;
}
~TrieNode() {
for (auto child : children)
delete child;
}
};
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(auto c : word) {
TrieNode *child = cur->fchild(c);
if(child)
cur = child;
else {
child = new TrieNode (c);
cur->children.push_back(child);
cur = child;
}
}
cur->isend = true;
}
// Returns if the word is in the trie.
bool search(string word) {
TrieNode *cur = root;
for(auto c : word) {
TrieNode *child = cur->fchild(c);
if (child)
cur = child;
else
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(auto c : prefix) {
TrieNode *child = cur->fchild(c);
if (child)
cur = child;
else
return false;
}
return true;
}
private:
TrieNode* root;
};
// Your Trie object will be instantiated and called as such:
// Trie trie;
// trie.insert("somestring");
// trie.search("key");