[Leetcode]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].

要求合并若干个区间~记得先把intervals按start值排序~

# Definition for an interval.
# class Interval:
#     def __init__(self, s=0, e=0):
#         self.start = s
#         self.end = e

class Solution:
    # @param intervals, a list of Interval
    # @return a list of Interval
    def merge(self, intervals):
        if intervals is None or len(intervals) == 0:
            return []
        intervals.sort(key = lambda x: x.start)
        #intervals.sort(cmp = lambda x, y: cmp(x.start, y.start) or (x.start == y.start and cmp(x.end,y.end)))
        res = []; prev = Start = End = None
        for curr in intervals:
            if prev:
                if curr.start <= End:
                    End = max(End, curr.end)
                else:
                    res.append([Start, End])
                    Start, End = curr.start, curr.end
            else:
                Start, End = curr.start, curr.end
            prev = curr
        res.append([Start, End])
        return res