【LeetCode with Python】 Merge Intervals

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原题页面： https://oj.leetcode.com/problems/merge-intervals/
题目类型：
难度评价：★
本文地址： http://blog.youkuaiyun.com/nerv3x3/article/details/3465927

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].

合并相连的区间。基本思路是，首先按起点start对所有区间排序，然后通过一次遍历来合并相连的区间。

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 len(intervals) <= 1:
            return intervals

        intervals.sort(lambda x, y: cmp(x.start, y.start))
        new_intervals = [ ]
        last_interval = intervals[0]
        for i in range(1, len(intervals)):
            if intervals[i].start >= last_interval.start and intervals[i].start <= last_interval.end:
                if intervals[i].end >= last_interval.start and intervals[i].end <= last_interval.end:
                    pass
                else:
                    last_interval.end = intervals[i].end
            else:
                new_intervals.append(last_interval)
                last_interval = intervals[i]
        new_intervals.append(last_interval)

        return new_intervals