Top K Frequent Elements

要点：

java：

• PriorityQueue的definition：Comparator：是一个generic interface，所以new Comparator()：加括号表示，同时implement interface 用 {}。内部实现@Override int compare() function
• 队列操作：offer/poll，map：put/get，set：add/get
• anonymous class的function是可以直接access外部变量的，比如这题的umap

class Solution(object):    def topKFrequent(self, nums, k):        """        :type nums: List[int]        :type k: int        :rtype: List[int]        """        from collections import Counter        from heapq import *        d = [(cnt, num) for num, cnt in Counter(nums).items()]        h = []        for i in xrange(k):            heappush(h, d[i])                    for i in xrange(k, len(d)):            if h[0][0]