729. My Calendar I

https://leetcode.com/problems/my-calendar-i/description/

Description

Implement a MyCalendar class to store your events. A new event can be added if adding the event will not cause a double booking.

Your class will have the method, book(int start, int end). Formally, this represents a booking on the half open interval [start, end), the range of real numbers x such that start <= x < end.

A double booking happens when two events have some non-empty intersection (ie., there is some time that is common to both events.)

For each call to the method MyCalendar.book, return true if the event can be added to the calendar successfully without causing a double booking. Otherwise, return false and do not add the event to the calendar.

Your class will be called like this:
MyCalendar cal = new MyCalendar(); MyCalendar.book(start, end)

Example 1:

MyCalendar();
MyCalendar.book(10, 20); // returns true
MyCalendar.book(15, 25); // returns false
MyCalendar.book(20, 30); // returns true

Explanation:

The first event can be booked. The second can't because time 15 is already booked by another event.
The third event can be booked, as the first event takes every time less than 20, but not including 20.

Note:
The number of calls to MyCalendar.book per test case will be at most 1000.
In calls to MyCalendar.book(start, end), start and end are integers in the range [0, 10^9].

Solution

Solution-1

二叉树的方式递归解决：

from collections import namedtuple
Event = namedtuple('Event', 'start end')
class Node:
    def __init__(self, event):
        self.value = event
        self.left = None
        self.right = None
class MyCalendar(object):
    def __init__(self):
        self.tree = None
    def is_confilict(self, e1, e2):
        if e1.end <= e2.start or e2.end<=e1.start:
            return False
        return True
    def add_event(self, root, e):
        if self.is_confilict(root.value, e):
            return False
        else:
            if e.end <= root.value.start:
                if root.left == None:
                    root.left = Node(e)
                    return True
                else:
                    return self.add_event(root.left, e)
            else:
                if root.right == None:
                    root.right = Node(e)
                    return True
                else:
                    return self.add_event(root.right, e)
    def book(self, start, end):
        """
        :type start: int
        :type end: int
        :rtype: bool
        """
        if self.tree==None:
            self.tree = Node(Event(start, end))
            return True
        return self.add_event(self.tree, Event(start, end))

LeetCode 测试运行：1063 ms。

Solution-2

用二分查找+list的方式代替树结构：

import bisect
class MyCalendar(object):
    def __init__(self):
        self.events = []
    def book(self, start, end):
        """
        :type start: int
        :type end: int
        :rtype: bool
        """
        p = bisect.bisect_left(self.events, (start, end))
        for i in (0, 1, -1):
            t = p+i
            if 0<=t<len(self.events) and not(
            self.events[t][0]>=end or self.events[t][1]<=start):
                return False
        self.events.insert(p, (start, end))
        return True

LeetCode 测试运行： 257 ms。