iOS时间合并

合并同一时间的课程，同一时间可能有多个课程，比如13:30-14:00 13:40-14:40

//递归实现
-(void)mergeClassSchedule:(NSMutableArray*)ary
retArray:(NSMutableArray*)retAry
beginDate:(NSDate*)beginDate
endDate:(NSDate*)endDate
{
NSMutableArray *groupAry=[NSMutableArray new];
if ([ary count]>0) {
[retAry addObject:groupAry];
}
while ([ary count]>0)
{

XSClassScheduleModel *classSchedulemodel=[ary objectAtIndex:0];
if (beginDate==nil)
{
beginDate=[XSUtil str2DateEx:classSchedulemodel.BeginDateTimeUTC];
endDate=[XSUtil str2DateEx:classSchedulemodel.EndDateTimeUTC];

[groupAry addObject:classSchedulemodel];

[ary removeObjectAtIndex:0];
}
else
{
NSDate *beginDate2=[XSUtil str2DateEx:classSchedulemodel.BeginDateTimeUTC];
NSDate *endDate2=[XSUtil str2DateEx:classSchedulemodel.EndDateTimeUTC];

if (([beginDate compare:beginDate2]==NSOrderedAscending || [beginDate compare:beginDate2]==NSOrderedSame)
&& [endDate compare:beginDate2]==NSOrderedDescending)
{
[groupAry addObject:classSchedulemodel];
[ary removeObjectAtIndex:0];
endDate=[endDate compare:endDate2]==NSOrderedAscending?endDate2:endDate;
}
else
{

beginDate=nil;
[self mergeClassSchedule:ary retArray:retAry beginDate:beginDate endDate:endDate];

}

}
}
}