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class Solution {public:	int ladderLength(string start, string end, unordered_set
   
     &dict) {		// Start typing your C/C++ solution below		// DO NOT write int main() function		//BFS(because all edge is 1) to find the minimum path		//O(n*len*26)		//shortest path O(n^2) will be TLE		queue
    
     
      > q;		unordered_set
      
        visited;		q.push(make_pair(start, 1));		visited.insert(start);		while (!q.empty())		{			string curStr = q.front().first;			int curStep = q.front().second;			q.pop();			for (int i = 0; i < curStr.size(); ++i)			{				string tmp = curStr;				for (int j = 0; j < 26; ++j)				{					tmp[i] = j+'a';					if(tmp == end)						return curStep+1;					if(visited.find(tmp) == visited.end() && dict.find(tmp) != dict.end())					{						q.push(make_pair(tmp, curStep+1));						visited.insert(tmp);					}				}			}		}		return 0;	}};
      
     
    
   

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