# [LeetCode] Implement Magic Dictionary 实现神奇字典

Implement a magic directory with buildDict, and search methods.

For the method buildDict, you'll be given a list of non-repetitive words to build a dictionary.

For the method search, you'll be given a word, and judge whether if you modify exactly one character into another character in this word, the modified word is in the dictionary you just built.

Example 1:

Input: buildDict(["hello", "leetcode"]), Output: Null
Input: search("hello"), Output: False
Input: search("hhllo"), Output: True
Input: search("hell"), Output: False
Input: search("leetcoded"), Output: False


Note:

1. You may assume that all the inputs are consist of lowercase letters a-z.
2. For contest purpose, the test data is rather small by now. You could think about highly efficient algorithm after the contest.
3. Please remember to RESET your class variables declared in class MagicDictionary, as static/class variables are persisted across multiple test cases. Please see here for more details.

class MagicDictionary {
public:
/** Initialize your data structure here. */
MagicDictionary() {}

/** Build a dictionary through a list of words */
void buildDict(vector<string> dict) {
for (string word : dict) {
m[word.size()].push_back(word);
}
}

/** Returns if there is any word in the trie that equals to the given word after modifying exactly one character */
bool search(string word) {
for (string str : m[word.size()]) {
int cnt = 0, i = 0;
for (; i < word.size(); ++i) {
if (word[i] == str[i]) continue;
if (word[i] != str[i] && cnt == 1) break;
++cnt;
}
if (i == word.size() && cnt == 1) return true;
}
return false;
}

private:
unordered_map<int, vector<string>> m;
};

class MagicDictionary {
public:
/** Initialize your data structure here. */
MagicDictionary() {}

/** Build a dictionary through a list of words */
void buildDict(vector<string> dict) {
for (string word : dict) s.insert(word);
}

/** Returns if there is any word in the trie that equals to the given word after modifying exactly one character */
bool search(string word) {
for (int i = 0; i < word.size(); ++i) {
char t = word[i];
for (char c = 'a'; c <= 'z'; ++c) {
if (c == t) continue;
word[i] = c;
if (s.count(word)) return true;
}
word[i] = t;
}
return false;
}

private:
unordered_set<string> s;
};

Implement Trie (Prefix Tree)

https://discuss.leetcode.com/topic/103004/c-clean-code

https://discuss.leetcode.com/topic/102992/easy-14-lines-java-solution-hashmap

LeetCode All in One 题目讲解汇总(持续更新中...)

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posted @ 2017-09-29 21:52  Grandyang  阅读(4268)  评论(1编辑  收藏  举报