题目如下：

解题思路：因为given list长度最多是50，我的解法就比较随意了，直接用一个嵌套的循环，判断数组中每个元素是否是其他的subsequence,最后找出不属于任何元素subsequence的最长元素即可。

代码如下：

class Solution(object):    def isSubsequence(self, a, b):        """        :type a: str        :type b: str        :rtype: int        """        s = b        for i in a:            inx = s.find(i)            if inx == -1:                return False            s = s[inx+1:]        return True    def findLUSlength(self, strs):        """        :type strs: List[str]        :rtype: int        """        def cmpf(v1,v2):            return len(v2) - len(v1)        strs.sort(cmp = cmpf)        if len(strs) == 0 or len(strs[0]) == 0:            return -1        res = -1        visit = [0 for x in strs]        for i in range(len(strs)):            if visit[i] == 1:                continue            tmp = False            for j in range(len((strs))):                if i == j:                    continue                tmp = self.isSubsequence(strs[i],strs[j])                if tmp == True:                    visit[i] = 1        for i in xrange(len(visit)):            if visit[i] == 0:                return len(strs[i])        return -1