LeetCode知识点总结 - 1353

LeetCode 1353. Maximum Number of Events That Can Be Attended

考点	难度
Greedy	Easy

题目

You are given an array of events where events[i] = [startDayi, endDayi]. Every event i starts at startDayi and ends at endDayi.

You can attend an event i at any day d where startTimei <= d <= endTimei. You can only attend one event at any time d.

Return the maximum number of events you can attend.

思路

priority queue，所有events按开始日顺序加到priority queue里，从day 1开始参加end最早的events，并且把已经结束的events从queue里去掉

答案

class Solution(object):
    def maxEvents(self, A):
        A.sort(reverse=1)
        h = []
        res = d = 0
        while A or h:
            if not h: d = A[-1][0]
            while A and A[-1][0] <= d:
                heapq.heappush(h, A.pop()[1])
            heapq.heappop(h)
            res += 1
            d += 1
            while h and h[0] < d:
                heapq.heappop(h)
        return res