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Merge Intervals

Given a collection of intervals, merge all overlapping intervals.

For example,
Given [1,3],[2,6],[8,10],[15,18],
return [1,6],[8,10],[15,18].

这题和Insert Interval类似,但是难度要低.主要在于我们可以先对全部区间做排序.区间开头已经排完序后, 则后加入的区间b相比于开始的区间a, b.start >= a.start. 判断重合则只需要b.start <= a.end.

代码如下:

# Definition for an interval.# class Interval(object):#     def __init__(self, s=0, e=0):#         self.start = s#         self.end = eclass Solution(object):    def merge(self, intervals):        """        :type intervals: List[Interval]        :rtype: List[Interval]        """        #sweep line        if not intervals:            return []        intervals.sort(key = lambda x: (x.start,x.end))        res = [intervals[0]]        for inter in intervals[1:]:            if inter.start > res[-1].end: #不重合                res.append(inter)            else:                         #有重合                if inter.end > res[-1].end:                    res[-1].end = inter.end        return res      

 

Merge Intervals