設定一個佇列儲存(nowword,count) 設定一個字典儲存候選單詞當q為空是找不到這樣的順序

class Solution(object):
    def ladderLength(self, beginWord, endWord, wordList):
        """
        :type beginWord: str
        :type endWord: str
        :type wordList: List[str]
        :rtype: int
        """
        dict1={}
        for w in wordList:
            if not w in dict1:
                dict1[w]=1 
            else:
                dict1[w]+=1
        q=[(beginWord,1)]
        while q:
            t,l = q.pop(0)
            if t == endWord:
                return l
            for i in range(len(t)):
                left = t[:i]
                right = t[i+1:]
                for s in 'abcdefghijklmnopqrstuvwxyz':
                    if s!=t[i]:
                        nextWord = left+s+right
                        if nextWord in dict1 and dict1[nextWord]>0:
                            q.append((nextWord,l+1))
                            dict1[nextWord]-=1
        return 0