lintcode-473-单词的添加与查找

473-单词的添加与查找

思路

code

/**
* Your Trie object will be instantiated and called as such:
* Trie trie;
* trie.insert("lintcode");
* trie.search("lint"); will return false
* trie.startsWith("lint"); will return true
*/
class TrieNode {
public:
// Initialize your data structure here.
char c;
TrieNode * next[26];
bool isEnd;

TrieNode() {
c = ' ';
for (int i = 0; i < 26; i++) {
next[i] = nullptr;
}
isEnd = false;
}

TrieNode(char c) {
this->c = c;
for (int i = 0; i < 26; i++) {
next[i] = nullptr;
}
isEnd = false;
}
};

class WordDictionary {
private:
TrieNode* root;

public:
WordDictionary() {
root = new TrieNode();
}

// Adds a word into the data structure.
void addWord(string word) {
// Write your code here
TrieNode* curNode = root;
for (int i = 0; i < word.size(); i++) {
if (curNode->next[word[i] - 'a'] != nullptr) {
curNode = curNode->next[word[i] - 'a'];
}
else {
TrieNode* node = new TrieNode(word[i]);
curNode->next[word[i] - 'a'] = node;
curNode = node;
}
}
curNode->isEnd = true;
}

// Returns if the word is in the data structure. A word could
// contain the dot character '.' to represent any one letter.
bool search(string word) {
// Write your code here
return search(word, root);
}

bool search(string word, TrieNode* root) {
if (word.size() == 0 && root != NULL) {
return root->isEnd;
}
else if (word[0] != '.' && root != NULL) {
return search(word.substr(1, word.size() - 1), root->next[word[0] - 'a']);
}
else if (word[0] == '.' && root != NULL) {
bool result = false;
for (int i = 0; i < 26; i++) {
if (root->next[i] != nullptr) {
result = result | search(word.substr(1, word.size() - 1), root->next[i]);
}
}
return result;
}
else if (root == NULL) {
return false;
}
}
};

// Your WordDictionary object will be instantiated and called as such:
// WordDictionary wordDictionary;
// wordDictionary.addWord("word");
// wordDictionary.search("pattern");