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Description

You are implementing a program to use as your calendar. We can add a new event if adding the event will not cause a triple booking.

A triple booking happens when three events have some non-empty intersection (i.e., some moment is common to all the three events.).

The event can be represented as a pair of integers start and end that represents a booking on the half-open interval [start, end), the range of real numbers x such that start <= x < end.

Implement the MyCalendarTwo class:

  • MyCalendarTwo() Initializes the calendar object.
  • boolean book(int start, int end) Returns true if the event can be added to the calendar successfully without causing a triple booking. Otherwise, return false and do not add the event to the calendar.

 

Example 1:

Input
["MyCalendarTwo", "book", "book", "book", "book", "book", "book"]
[[], [10, 20], [50, 60], [10, 40], [5, 15], [5, 10], [25, 55]]
Output
[null, true, true, true, false, true, true]

Explanation
MyCalendarTwo myCalendarTwo = new MyCalendarTwo();
myCalendarTwo.book(10, 20); // return True, The event can be booked. 
myCalendarTwo.book(50, 60); // return True, The event can be booked. 
myCalendarTwo.book(10, 40); // return True, The event can be double booked. 
myCalendarTwo.book(5, 15);  // return False, The event cannot be booked, because it would result in a triple booking.
myCalendarTwo.book(5, 10); // return True, The event can be booked, as it does not use time 10 which is already double booked.
myCalendarTwo.book(25, 55); // return True, The event can be booked, as the time in [25, 40) will be double booked with the third event, the time [40, 50) will be single booked, and the time [50, 55) will be double booked with the second event.

 

Constraints:

  • 0 <= start < end <= 109
  • At most 1000 calls will be made to book.

Solutions

Python3

from sortedcontainers import SortedDict


class MyCalendarTwo:
    def __init__(self):
        self.sd = SortedDict()

    def book(self, start: int, end: int) -> bool:
        self.sd[start] = self.sd.get(start, 0) + 1
        self.sd[end] = self.sd.get(end, 0) - 1
        s = 0
        for v in self.sd.values():
            s += v
            if s > 2:
                self.sd[start] -= 1
                self.sd[end] += 1
                return False
        return True


# Your MyCalendarTwo object will be instantiated and called as such:
# obj = MyCalendarTwo()
# param_1 = obj.book(start,end)
class Node:
    def __init__(self, l, r):
        self.left = None
        self.right = None
        self.l = l
        self.r = r
        self.mid = (l + r) >> 1
        self.v = 0
        self.add = 0


class SegmentTree:
    def __init__(self):
        self.root = Node(1, int(1e9 + 1))

    def modify(self, l, r, v, node=None):
        if l > r:
            return
        if node is None:
            node = self.root
        if node.l >= l and node.r <= r:
            node.v += v
            node.add += v
            return
        self.pushdown(node)
        if l <= node.mid:
            self.modify(l, r, v, node.left)
        if r > node.mid:
            self.modify(l, r, v, node.right)
        self.pushup(node)

    def query(self, l, r, node=None):
        if l > r:
            return 0
        if node is None:
            node = self.root
        if node.l >= l and node.r <= r:
            return node.v
        self.pushdown(node)
        v = 0
        if l <= node.mid:
            v = max(v, self.query(l, r, node.left))
        if r > node.mid:
            v = max(v, self.query(l, r, node.right))
        return v

    def pushup(self, node):
        node.v = max(node.left.v, node.right.v)

    def pushdown(self, node):
        if node.left is None:
            node.left = Node(node.l, node.mid)
        if node.right is None:
            node.right = Node(node.mid + 1, node.r)
        if node.add:
            node.left.v += node.add
            node.right.v += node.add
            node.left.add += node.add
            node.right.add += node.add
            node.add = 0

class MyCalendarTwo:

    def __init__(self):
        self.tree = SegmentTree()

    def book(self, start: int, end: int) -> bool:
        if self.tree.query(start + 1, end) >= 2:
            return False
        self.tree.modify(start + 1, end, 1)
        return True


# Your MyCalendarTwo object will be instantiated and called as such:
# obj = MyCalendarTwo()
# param_1 = obj.book(start,end)

Java

class MyCalendarTwo {
    private Map<Integer, Integer> tm = new TreeMap<>();

    public MyCalendarTwo() {

    }

    public boolean book(int start, int end) {
        tm.put(start, tm.getOrDefault(start, 0) + 1);
        tm.put(end, tm.getOrDefault(end, 0) - 1);
        int s = 0;
        for (int v : tm.values()) {
            s += v;
            if (s > 2) {
                tm.put(start, tm.get(start) - 1);
                tm.put(end, tm.get(end) + 1);
                return false;
            }
        }
        return true;
    }
}

/**
 * Your MyCalendarTwo object will be instantiated and called as such:
 * MyCalendarTwo obj = new MyCalendarTwo();
 * boolean param_1 = obj.book(start,end);
 */
class Node {
    Node left;
    Node right;
    int l;
    int r;
    int mid;
    int v;
    int add;
    public Node(int l, int r) {
        this.l = l;
        this.r = r;
        this.mid = (l + r) >> 1;
    }
}

class SegmentTree {
    private Node root = new Node(1, (int) 1e9 + 1);

    public SegmentTree() {
    }

    public void modify(int l, int r, int v) {
        modify(l, r, v, root);
    }

    public void modify(int l, int r, int v, Node node) {
        if (l > r) {
            return;
        }
        if (node.l >= l && node.r <= r) {
            node.v += v;
            node.add += v;
            return;
        }
        pushdown(node);
        if (l <= node.mid) {
            modify(l, r, v, node.left);
        }
        if (r > node.mid) {
            modify(l, r, v, node.right);
        }
        pushup(node);
    }

    public int query(int l, int r) {
        return query(l, r, root);
    }

    public int query(int l, int r, Node node) {
        if (l > r) {
            return 0;
        }
        if (node.l >= l && node.r <= r) {
            return node.v;
        }
        pushdown(node);
        int v = 0;
        if (l <= node.mid) {
            v = Math.max(v, query(l, r, node.left));
        }
        if (r > node.mid) {
            v = Math.max(v, query(l, r, node.right));
        }
        return v;
    }

    public void pushup(Node node) {
        node.v = Math.max(node.left.v, node.right.v);
    }

    public void pushdown(Node node) {
        if (node.left == null) {
            node.left = new Node(node.l, node.mid);
        }
        if (node.right == null) {
            node.right = new Node(node.mid + 1, node.r);
        }
        if (node.add != 0) {
            Node left = node.left, right = node.right;
            left.add += node.add;
            right.add += node.add;
            left.v += node.add;
            right.v += node.add;
            node.add = 0;
        }
    }
}

class MyCalendarTwo {
    private SegmentTree tree = new SegmentTree();

    public MyCalendarTwo() {
    }

    public boolean book(int start, int end) {
        if (tree.query(start + 1, end) >= 2) {
            return false;
        }
        tree.modify(start + 1, end, 1);
        return true;
    }
}

/**
 * Your MyCalendarTwo object will be instantiated and called as such:
 * MyCalendarTwo obj = new MyCalendarTwo();
 * boolean param_1 = obj.book(start,end);
 */

C++

class MyCalendarTwo {
public:
    map<int, int> m;

    MyCalendarTwo() {
    }

    bool book(int start, int end) {
        ++m[start];
        --m[end];
        int s = 0;
        for (auto& [_, v] : m) {
            s += v;
            if (s > 2) {
                --m[start];
                ++m[end];
                return false;
            }
        }
        return true;
    }
};

/**
 * Your MyCalendarTwo object will be instantiated and called as such:
 * MyCalendarTwo* obj = new MyCalendarTwo();
 * bool param_1 = obj->book(start,end);
 */
class Node {
public:
    Node* left;
    Node* right;
    int l;
    int r;
    int mid;
    int v;
    int add;

    Node(int l, int r) {
        this->l = l;
        this->r = r;
        this->mid = (l + r) >> 1;
        this->left = this->right = nullptr;
        v = add = 0;
    }
};

class SegmentTree {
private:
    Node* root;

public:
    SegmentTree() {
        root = new Node(1, 1e9 + 1);
    }

    void modify(int l, int r, int v) {
        modify(l, r, v, root);
    }

    void modify(int l, int r,int v, Node* node) {
        if (l > r) return;
        if (node->l >= l && node->r <= r)
        {
            node->v += v;
            node->add += v;
            return;
        }
        pushdown(node);
        if (l <= node->mid) modify(l, r, v, node->left);
        if (r > node->mid) modify(l, r, v, node->right);
        pushup(node);
    }

    int query(int l, int r) {
        return query(l, r, root);
    }

    int query(int l, int r, Node* node) {
        if (l > r) return 0;
        if (node->l >= l && node-> r <= r) return node->v;
        pushdown(node);
        int v = 0;
        if (l <= node->mid) v = max(v, query(l, r, node->left));
        if (r > node->mid) v = max(v, query(l, r, node->right));
        return v;
    }

    void pushup(Node* node) {
        node->v = max(node->left->v, node->right->v);
    }

    void pushdown(Node* node) {
        if (!node->left) node->left = new Node(node->l, node->mid);
        if (!node->right) node->right = new Node(node->mid + 1, node->r);
        if (node->add)
        {
            Node* left = node->left;
            Node* right = node->right;
            left->v += node->add;
            right->v += node->add;
            left->add += node->add;
            right->add += node->add;
            node->add = 0;
        }
    }
};

class MyCalendarTwo {
public:
    SegmentTree* tree = new SegmentTree();

    MyCalendarTwo() {

    }

    bool book(int start, int end) {
        if (tree->query(start + 1, end) >= 2) return false;
        tree->modify(start + 1, end, 1);
        return true;
    }
};

/**
 * Your MyCalendarTwo object will be instantiated and called as such:
 * MyCalendarTwo* obj = new MyCalendarTwo();
 * bool param_1 = obj->book(start,end);
 */

Go

type MyCalendarTwo struct {
	*redblacktree.Tree
}

func Constructor() MyCalendarTwo {
	return MyCalendarTwo{redblacktree.NewWithIntComparator()}
}

func (this *MyCalendarTwo) Book(start int, end int) bool {
	add := func(key, val int) {
		if v, ok := this.Get(key); ok {
			this.Put(key, v.(int)+val)
		} else {
			this.Put(key, val)
		}
	}
	add(start, 1)
	add(end, -1)
	s := 0
	it := this.Iterator()
	for it.Next() {
		s += it.Value().(int)
		if s > 2 {
			add(start, -1)
			add(end, 1)
			return false
		}
	}
	return true
}

/**
 * Your MyCalendarTwo object will be instantiated and called as such:
 * obj := Constructor();
 * param_1 := obj.Book(start,end);
 */
type node struct {
	left      *node
	right     *node
	l, mid, r int
	v, add    int
}

func newNode(l, r int) *node {
	return &node{
		l:   l,
		r:   r,
		mid: int(uint(l+r) >> 1),
	}
}

func max(x, y int) int {
	if x > y {
		return x
	}
	return y
}

type segmentTree struct {
	root *node
}

func newSegmentTree() *segmentTree {
	return &segmentTree{
		root: newNode(1, 1e9+1),
	}
}

func (t *segmentTree) modify(l, r, v int, n *node) {
	if l > r {
		return
	}
	if n.l >= l && n.r <= r {
		n.v += v
		n.add += v
		return
	}
	t.pushdown(n)
	if l <= n.mid {
		t.modify(l, r, v, n.left)
	}
	if r > n.mid {
		t.modify(l, r, v, n.right)
	}
	t.pushup(n)
}

func (t *segmentTree) query(l, r int, n *node) int {
	if l > r {
		return 0
	}
	if n.l >= l && n.r <= r {
		return n.v
	}
	t.pushdown(n)
	v := 0
	if l <= n.mid {
		v = max(v, t.query(l, r, n.left))
	}
	if r > n.mid {
		v = max(v, t.query(l, r, n.right))
	}
	return v
}

func (t *segmentTree) pushup(n *node) {
	n.v = max(n.left.v, n.right.v)
}

func (t *segmentTree) pushdown(n *node) {
	if n.left == nil {
		n.left = newNode(n.l, n.mid)
	}
	if n.right == nil {
		n.right = newNode(n.mid+1, n.r)
	}
	if n.add != 0 {
		n.left.add += n.add
		n.right.add += n.add
		n.left.v += n.add
		n.right.v += n.add
		n.add = 0
	}
}

type MyCalendarTwo struct {
	tree *segmentTree
}

func Constructor() MyCalendarTwo {
	return MyCalendarTwo{newSegmentTree()}
}

func (this *MyCalendarTwo) Book(start int, end int) bool {
	if this.tree.query(start+1, end, this.tree.root) >= 2 {
		return false
	}
	this.tree.modify(start+1, end, 1, this.tree.root)
	return true
}

/**
 * Your MyCalendarTwo object will be instantiated and called as such:
 * obj := Constructor();
 * param_1 := obj.Book(start,end);
 */

...