676. Implement magic dictionary

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.

 解法1

#include<string>
#include<vector>
#include<iostream>
#include<unordered_map>
using namespace std;
class MagicDictionary{
    unordered_map<int,vector<string>> m;
public:
    MagicDictionary(){

    }
    void buildDict(vector<string> dict){
        for(string word: dict){
            m[word.size()].push_back(word);
        }
    }
    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;
    }
};

int main(){
    MagicDictionary magicDictionary;
    magicDictionary.buildDict({"hello","leetcode"});
    cout<<magicDictionary.search("hello")<<endl;
    cout<<magicDictionary.search("hhllo")<<endl;
    cout<<magicDictionary.search("hell")<<endl;
    cout<<magicDictionary.search("leetcoded")<<endl;
    return 0;

}

 解法2

#include<string>
#include<vector>
#include<iostream>
#include<unordered_map>
#include<unordered_set>
using namespace std;
class MagicDictionary{
    unordered_set<string> st;
public:
    MagicDictionary(){

    }
    void buildDict(vector<string> dict){
        for(string word: dict){
            st.insert(word);
        }
    }
    bool search(string word){
        for(int i=0;i<word.size();++i){
            char tmp=word[i];
            for(char c='a';c<='z';++c){
                if(c==tmp)
                    continue;
                word[i]=c;
                if(st.find(word)!=st.end()){
                    return true;
                }
            }
            word[i]=tmp;
        }
        return false;
    }
};

int main(){
    MagicDictionary magicDictionary;
    magicDictionary.buildDict({"hello","leetcode"});
    cout<<magicDictionary.search("hello")<<endl;
    cout<<magicDictionary.search("hhllo")<<endl;
    cout<<magicDictionary.search("hell")<<endl;
    cout<<magicDictionary.search("leetcoded")<<endl;
    return 0;

}

参考