【leetcode】1122. Relative Sort Array

题目如下：

解题思路：题目很简单，求出arr1和arr2的交集以及交集中每个元素出现的次数，按元素在arr2中的顺序排列好，最后再加上arr1中不在arr2里面的元素即可。

代码如下：

class Solution(object):

    def relativeSortArray(self, arr1, arr2):

        """

        :type arr1: List[int]

        :type arr2: List[int]

        :rtype: List[int]

        """

        dic = {}

        for i in arr2:

            dic[i] = 1

        not_in_2 = []

        dic1 = {}

        for i in arr1:

            if i in dic:

                dic1[i] = dic1.setdefault(i,0) + 1

            else:

                not_in_2.append(i)

        res = []

        for i in arr2:

            res += [i] * dic1[i]

        return res + sorted(not_in_2)