Smallest Number in Unlimited Set

Imagine you have a collection that initially contains every positive integer starting from 1 and going upwards indefinitely, like [1, 2, 3, 4, 5, ...].

Your task is to create a class called MinInfiniteSet that supports the following operations:

• MinInfiniteSet(): Initializes the object so that it contains all positive integers.
• int getMin(): Removes and returns the smallest number currently present in the set.
• void restore(int val): Adds a positive integer val back to the set, but only if it is not already present.

Examples

MinInfiniteSet minSet = new MinInfiniteSet();
minSet.restore(3);          // 3 is already in the set, so no changes made.
minSet.getMin();            // Returns 1 and removes it from the set.
minSet.getMin();            // Returns 2 and removes it.
minSet.getMin();            // Returns 3 and removes it.
minSet.restore(1);          // 1 is added back to the set.
minSet.getMin();            // Returns 1 since it was restored.
minSet.getMin();            // Returns 4 and removes it.
minSet.getMin();            // Returns 5 and removes it.
  

Constraints

• 1 ≤ val ≤ 2000
• At most 1200 calls will be made in total to getMin() and restore().