Leetcode-127-Word-Ladder.cc

class Solution {
    int dist(string &s, string &t){
        int cnt=0;
        for(int i=0;i<s.size();i++)
            if(s[i]!=t[i])
                cnt++;
        
        return cnt;
    }
public:
    int ladderLength(string beginWord, string endWord, vector<string>& wordList) {
        if(wordList.empty())
            return 0;
        
        queue<string> q;
        int level=0;
        unordered_set<string> s(wordList.begin(),wordList.end());
        
        if(s.count(endWord)==0)
            return 0;
        q.push(beginWord);
        
        while(!q.empty()){
            int sz=q.size();
            level++;
            while(sz--){
                string cur=q.front();
                q.pop();
                
                if(s.count(cur)>0)
                    s.erase(cur);
                
                if(cur.compare(endWord)==0)
                    return level;
             
                for(auto candi:s){
                    if(dist(candi,cur)==1)
                        q.push(candi);
                }
            }
            
        }
        
        return 0;
    }
};

Time Limit Exceeded. 30/40 cases passed.