Method letterCombinations

String/LetterCombinationsOfAPhoneNumber.py:36–63

:type digits: str :rtype: List[str]

(self, digits)

"""
class Solution(object):
    def letterCombinations(self, digits):
        """
        :type digits: str
        :rtype: List[str]
        """
        maps = {
            '2': 'abc',
            '3': 'def',
            '4': 'ghi',
            '5': 'jkl',
            '6': 'mno',
            '7': 'pqrs',
            '8': 'tuv',
            '9': 'wxyz'
        }
        
        result = []
        
        def reduce_abc(strs, currentStr=""):
            if not strs:
                return currentStr
            else:
                for i in maps[strs[0]]:
                    x = reduce_abc(strs[1:], currentStr=currentStr+i)
                    if x:
                        result.append(x)
        reduce_abc(digits)
        return result