Question

729. My Calendar I

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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 double booking.

A double booking happens when two events have some non-empty intersection (i.e., some moment is common to both 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 MyCalendar class:

• MyCalendar() 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 double booking. Otherwise, return false and do not add the event to the calendar.

 

Example 1:

Input
["MyCalendar", "book", "book", "book"]
[[], [10, 20], [15, 25], [20, 30]]
Output
[null, true, false, true]

Explanation
MyCalendar myCalendar = new MyCalendar();
myCalendar.book(10, 20); // return True
myCalendar.book(15, 25); // return False, It can not be booked because time 15 is already booked by another event.
myCalendar.book(20, 30); // return True, The event can be booked, as the first event takes every time less than 20, but not including 20.

 

Constraints:

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

Solutions

Solution 1

from sortedcontainers import SortedDict


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

  def book(self, start: int, end: int) -> bool:
    idx = self.sd.bisect_right(start)
    if idx < len(self.sd) and end > self.sd.values()[idx]:
      return False
    self.sd[end] = start
    return True


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

import java.util.Map;
import java.util.TreeMap;

class MyCalendar {

  private final TreeMap<Integer, Integer> tm = new TreeMap<>();

  public MyCalendar() {
  }

  public boolean book(int start, int end) {
    Map.Entry<Integer, Integer> ent = tm.floorEntry(start);
    if (ent != null && ent.getValue() > start) {
      return false;
    }
    ent = tm.ceilingEntry(start);
    if (ent != null && ent.getKey() < end) {
      return false;
    }
    tm.put(start, end);
    return true;
  }
}

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

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

  MyCalendar() {
  }

  bool book(int start, int end) {
    ++m[start];
    --m[end];
    int s = 0;
    for (auto& [k, v] : m) {
      s += v;
      if (s > 1) {
        --m[start];
        ++m[end];
        return false;
      }
    }
    return true;
  }
};

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

type MyCalendar struct {
  rbt *redblacktree.Tree
}

func Constructor() MyCalendar {
  return MyCalendar{
    rbt: redblacktree.NewWithIntComparator(),
  }
}

func (this *MyCalendar) Book(start int, end int) bool {
  if p, ok := this.rbt.Floor(start); ok && p.Value.(int) > start {
    return false
  }
  if p, ok := this.rbt.Ceiling(start); ok && p.Key.(int) < end {
    return false
  }
  this.rbt.Put(start, end)
  return true
}

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

class MyCalendar {
  private calendar: number[][];

  constructor() {
    this.calendar = [];
  }

  book(start: number, end: number): boolean {
    for (const item of this.calendar) {
      if (end <= item[0] || item[1] <= start) {
        continue;
      }
      return false;
    }
    this.calendar.push([start, end]);
    return true;
  }
}

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

use std::collections::BTreeMap;

struct MyCalendar {
  bt: BTreeMap<i32, i32>,
}

/**
 * `&self` means the method takes an immutable reference.
 * If you need a mutable reference, change it to `&mut self` instead.
 */
impl MyCalendar {
  fn new() -> Self {
    MyCalendar {
      bt: BTreeMap::new(),
    }
  }

  fn book(&mut self, start: i32, end: i32) -> bool {
    if let Some((_, &val)) = self.bt.range(..=start).last() {
      println!("{} {} {}", start, end, val);
      if val > start {
        return false;
      }
    }
    if let Some((&key, _)) = self.bt.range(start..).next() {
      if key < end {
        return false;
      }
    }
    self.bt.insert(start, end);
    true
  }
}/**
 * Your MyCalendar object will be instantiated and called as such:
 * let obj = MyCalendar::new();
 * let ret_1: bool = obj.book(start, end);
 */