056. Merge Intervals

#!/usr/bin/env python3

__author__ = 'Wei Mu'

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

class Solution:
    def merge(self, intervals: 'List[Interval]') -> 'List[Interval]':
        
        ans = []
        
        while intervals != []:
            temp = intervals.pop(0)
            
            drop_list = [0]
            
            while drop_list != []:
                drop_list = []
                
                for i in range(len(intervals)):
                    temp, drop = self.merge_helper(temp, intervals[i])
                    
                    if drop == True:
                        drop_list.append(i)
                
                for j in drop_list[::-1]:
                    intervals.pop(j)
                
            ans.append(temp)
        
        return ans
                    
    def merge_helper(self, s1, s2):
        if s1.start > s2.end or s2.start > s1.end:
            return (s1, False)
        else:
            s1.start = min(s1.start, s2.start)
            s1.end = max(s1.end, s2.end)
            return (s1, True)