leetcode 720 - Longest Word in Dictionary

Posted 2022-03-25 bella2017

 

思路：Brute force + pruning

用不用set来存储输入的words都可以。

class Solution 
public:
    string longestWord(vector<string>& words) 
        string best;  //存储当前最优解
        //unordered_set<string> dict(words.begin(), words.end());
        for(const string& word: words)
            //pruning
            if(word.length()<best.length() || (word.length()==best.length()&& word>best))
                continue;
            string prefix;
            bool valid = true;
            for(int i=0; i<word.length()-1 && valid; ++i)
                prefix += word[i];
                if(find(words.begin(), words.end(), prefix)==words.end())
                //if(!dict.count(prefix))
                    valid = false;
            
            if(valid) best = word;
        
        return best;
    
;