title

problem link

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.

solution

判断是否有重叠区间，可以排序树实现，每个节点是(start, end), 每次插入依次判断

class MyCalendar {
private:
	vector<pair<int, int>> v;

public:
	MyCalendar() {
		v.clear();
	}

	bool book(int start, int end) {
		if (v.empty()) {
			v.push_back(make_pair(start, end));
			return true;
		}
		int index = -1;
		for (int i = 0; i < v.size(); i++) {
			if (start<v[i].second&&end>v[i].first)
				return false;
		}
		v.push_back(make_pair(start, end));
		return true;
	}
};

class Node:
    __slots__ = 'start', 'end', 'left', 'right'
    def __init__(self, start, end):
        self.start = start
        self.end = end
        self.left = self.right = None

    def insert(self, node):
        if node.start >= self.end:
            if not self.right:
                self.right = node
                return True
            return self.right.insert(node)
        elif node.end <= self.start:
            if not self.left:
                self.left = node
                return True
            return self.left.insert(node)
        else:
            return False

class MyCalendar(object):
    def __init__(self):
        self.root = None

    def book(self, start, end):
        if self.root is None:
            self.root = Node(start, end)
            return True
        return self.root.insert(Node(start, end))