题解 | #合并区间#

from functools import cmp_to_key
# class Interval:
#     def __init__(self, a=0, b=0):
#         self.start = a
#         self.end = b
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param intervals Interval类一维数组 
# @return Interval类一维数组
#
class Solution:
    def merge(self , intervals: List[Interval]) -> List[Interval]:
        # write code here
        # 方法一：方法会超时，但没理解为啥会超时
        # if not intervals:
        #     return []
        # intervals.sort(key=lambda x:x.start)
        # l, r = 0, 1
        # while r<len(intervals):
        #     if intervals[l].end<intervals[r].start:
        #         l += 1
        #         r += 1
        #     else:
        #         intervals[l].end = max(intervals[l].end,intervals[r].end)
        #         intervals.pop(r)
        # return intervals
        # 方法二
        if not intervals:
            return []
        intervals.sort(key=lambda x:x.start)
        res = []
        res.append(intervals[0])
        for i in range(1,len(intervals)):
            if intervals[i].start <= res[-1].end:
                res[-1].end = max(intervals[i].end, res[-1].end)
            else:
                res.append(intervals[i])
        return res