Question

2349. Design a Number Container System

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Description

Design a number container system that can do the following:

• Insert or Replace a number at the given index in the system.
• Return the smallest index for the given number in the system.

Implement the NumberContainers class:

• NumberContainers() Initializes the number container system.
• void change(int index, int number) Fills the container at index with the number. If there is already a number at that index, replace it.
• int find(int number) Returns the smallest index for the given number, or -1 if there is no index that is filled by number in the system.

 

Example 1:

Input
["NumberContainers", "find", "change", "change", "change", "change", "find", "change", "find"]
[[], [10], [2, 10], [1, 10], [3, 10], [5, 10], [10], [1, 20], [10]]
Output
[null, -1, null, null, null, null, 1, null, 2]

Explanation
NumberContainers nc = new NumberContainers();
nc.find(10); // There is no index that is filled with number 10. Therefore, we return -1.
nc.change(2, 10); // Your container at index 2 will be filled with number 10.
nc.change(1, 10); // Your container at index 1 will be filled with number 10.
nc.change(3, 10); // Your container at index 3 will be filled with number 10.
nc.change(5, 10); // Your container at index 5 will be filled with number 10.
nc.find(10); // Number 10 is at the indices 1, 2, 3, and 5. Since the smallest index that is filled with 10 is 1, we return 1.
nc.change(1, 20); // Your container at index 1 will be filled with number 20. Note that index 1 was filled with 10 and then replaced with 20. 
nc.find(10); // Number 10 is at the indices 2, 3, and 5. The smallest index that is filled with 10 is 2. Therefore, we return 2.

 

Constraints:

• 1 <= index, number <= 109
• At most 105 calls will be made in total to change and find.

Solutions

Solution 1

from sortedcontainers import SortedSet


class NumberContainers:
  def __init__(self):
    self.mp = {}
    self.t = defaultdict(SortedSet)

  def change(self, index: int, number: int) -> None:
    if index in self.mp:
      v = self.mp[index]
      self.t[v].remove(index)
    self.mp[index] = number
    self.t[number].add(index)

  def find(self, number: int) -> int:
    s = self.t[number]
    return s[0] if s else -1


# Your NumberContainers object will be instantiated and called as such:
# obj = NumberContainers()
# obj.change(index,number)
# param_2 = obj.find(number)

class NumberContainers {
  private Map<Integer, Integer> mp = new HashMap<>();
  private Map<Integer, TreeSet<Integer>> t = new HashMap<>();

  public NumberContainers() {
  }

  public void change(int index, int number) {
    if (mp.containsKey(index)) {
      int v = mp.get(index);
      t.get(v).remove(index);
      if (t.get(v).isEmpty()) {
        t.remove(v);
      }
    }
    mp.put(index, number);
    t.computeIfAbsent(number, k -> new TreeSet<>()).add(index);
  }

  public int find(int number) {
    return t.containsKey(number) ? t.get(number).first() : -1;
  }
}

/**
 * Your NumberContainers object will be instantiated and called as such:
 * NumberContainers obj = new NumberContainers();
 * obj.change(index,number);
 * int param_2 = obj.find(number);
 */

class NumberContainers {
public:
  map<int, int> mp;
  map<int, set<int>> t;

  NumberContainers() {
  }

  void change(int index, int number) {
    auto it = mp.find(index);
    if (it != mp.end()) {
      t[it->second].erase(index);
      it->second = number;
    } else
      mp[index] = number;
    t[number].insert(index);
  }

  int find(int number) {
    auto it = t.find(number);
    return it == t.end() || it->second.empty() ? -1 : *it->second.begin();
  }
};

/**
 * Your NumberContainers object will be instantiated and called as such:
 * NumberContainers* obj = new NumberContainers();
 * obj->change(index,number);
 * int param_2 = obj->find(number);
 */

type NumberContainers struct {
  mp map[int]int
  t  map[int]*redblacktree.Tree
}

func Constructor() NumberContainers {
  return NumberContainers{map[int]int{}, map[int]*redblacktree.Tree{}}
}

func (this *NumberContainers) Change(index int, number int) {
  if num, ok := this.mp[index]; ok {
    this.t[num].Remove(index)
  }
  this.mp[index] = number
  if this.t[number] == nil {
    this.t[number] = redblacktree.NewWithIntComparator()
  }
  this.t[number].Put(index, nil)
}

func (this *NumberContainers) Find(number int) int {
  s, ok := this.t[number]
  if !ok || s.Size() == 0 {
    return -1
  }
  return s.Left().Key.(int)
}

/**
 * Your NumberContainers object will be instantiated and called as such:
 * obj := Constructor();
 * obj.Change(index,number);
 * param_2 := obj.Find(number);
 */