Package g2301_2400.s2336_smallest_number_in_infinite_set

Class SmallestInfiniteSet

java.lang.Object

g2301_2400.s2336_smallest_number_in_infinite_set.SmallestInfiniteSet

public class SmallestInfiniteSet
extends Object

2336 - Smallest Number in Infinite Set.<p>Medium</p> <p>You have a set which contains all positive integers <code>[1, 2, 3, 4, 5, ...]</code>.</p> <p>Implement the <code>SmallestInfiniteSet</code> class:</p> <ul> <li><code>SmallestInfiniteSet()</code> Initializes the <strong>SmallestInfiniteSet</strong> object to contain <strong>all</strong> positive integers.</li> <li><code>int popSmallest()</code> <strong>Removes</strong> and returns the smallest integer contained in the infinite set.</li> <li><code>void addBack(int num)</code> <strong>Adds</strong> a positive integer <code>num</code> back into the infinite set, if it is <strong>not</strong> already in the infinite set.</li> </ul> <p><strong>Example 1:</strong></p> <p><strong>Input</strong></p> <p>[&ldquo;SmallestInfiniteSet&rdquo;, &ldquo;addBack&rdquo;, &ldquo;popSmallest&rdquo;, &ldquo;popSmallest&rdquo;, &ldquo;popSmallest&rdquo;, &ldquo;addBack&rdquo;, &ldquo;popSmallest&rdquo;, &ldquo;popSmallest&rdquo;, &ldquo;popSmallest&rdquo;]</p> <p>[ [], [2], [], [], [], [1], [], [], []]</p> <p><strong>Output:</strong></p> <p>[null, null, 1, 2, 3, null, 1, 4, 5]</p> <p><strong>Explanation:</strong></p> <pre><code> SmallestInfiniteSet smallestInfiniteSet = new SmallestInfiniteSet(); smallestInfiniteSet.addBack(2); // 2 is already in the set, so no change is made. smallestInfiniteSet.popSmallest(); // return 1, since 1 is the smallest number, and remove it from the set. smallestInfiniteSet.popSmallest(); // return 2, and remove it from the set. smallestInfiniteSet.popSmallest(); // return 3, and remove it from the set. smallestInfiniteSet.addBack(1); // 1 is added back to the set. smallestInfiniteSet.popSmallest(); // return 1, since 1 was added back to the set and // is the smallest number, and remove it from the set. smallestInfiniteSet.popSmallest(); // return 4, and remove it from the set. smallestInfiniteSet.popSmallest(); // return 5, and remove it from the set. </code></pre> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= num <= 1000</code></li> <li>At most <code>1000</code> calls will be made <strong>in total</strong> to <code>popSmallest</code> and <code>addBack</code>.</li> </ul>

Constructor Summary

Constructors

Constructor	Description
SmallestInfiniteSet()

Method Summary

Modifier and Type	Method	Description
void	addBack(int num)
int	popSmallest()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SmallestInfiniteSet

public SmallestInfiniteSet()

Method Details

popSmallest

public int popSmallest()

addBack

public void addBack(int num)