135 ms Python solution with bit manipulation

  • 0
    • Its easy to use binary to enumerate which char we will keep.
    • The key to speed up is I record all same locations, and store the number to maps[].
    • So, if binary number map[i] & x == x(x is the binary representation while enumerating), this means we have a word in dictionary which will have same abbr.
    class Solution(object):
        def minAbbreviation(self, target, dictionary):
            :type target: str
            :type dictionary: List[str]
            :rtype: str
            dictionary = [i for i in dictionary if len(i) == len(target)]
            if not dictionary:
                return str(len(target))
            # calculate the value to represent same locations
            maps = []
            for i in dictionary:
                mask = 0
                for j in xrange(len(target)):
                    if target[j] == i[j]:
                        mask |= (1 << j)
            res = target
            for i in xrange(1 << len(target)):
                for j in maps:
                    # This means same abbr
                    if i & j == i:
                # this is just to construct the abbr
                    pre = 0
                    tmpstr = ""
                    for j in xrange(len(target)):
                        if i & (1 << j):
                            if pre < j:
                                tmpstr += str(j - pre)
                            tmpstr += target[j]
                            pre = j + 1
                    if pre < len(target):
                        tmpstr += str(len(target) - pre)
                    if len(tmpstr) < len(res):
                        res = tmpstr
            return res

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