Meeting Rooms II(sort)

Given an array of meeting time intervals consisting of start and end times[[s1,e1],[s2,e2],...] (si < ei), find the minimum number of conference rooms required.

Example

Given intervals =[(0,30),(5,10),(15,20)], return2.

分析

起点终点拆开放入数组，数组按照时间先后和start end排序

最后遇start ++ 遇到end --

注意tuple的另一个写法 for _,d in times:

"""
Definition of Interval.
class Interval(object):
    def __init__(self, start, end):
        self.start = start
        self.end = end
"""
from operator import itemgetter


class Solution:
    """
    @param intervals: an array of meeting time intervals
    @return: the minimum number of conference rooms required
    """
    def minMeetingRooms(self, intervals):
        # Write your code here
        times = []
        for i in intervals:
            times.append((i.start,0))
            times.append((i.end,1))
        times.sort(key=itemgetter(0,1))
        mr = r=0
        for t in times:#for _,d in times:
            r+=1 if t[1]==0 else -1
            mr=max(mr,r)
        return mr

先降后升

class Solution:
    def minMeetingRooms(self, intervals: List[List[int]]) -> int:
        times = []
        for s,e in intervals:
            times.append((s,1))
            times.append((e,0))
        
        times.sort(key = lambda x: (x[0],x[1]))
        cur = res = 0
        for _,d in times:
            cur += 1 if d == 1 else -1
            res = max(res,cur)
        return res