Package g0401_0500.s0432_all_oone_data_structure

Class AllOne

java.lang.Object

g0401_0500.s0432_all_oone_data_structure.AllOne

public class AllOne
extends Object

432 - All O`one Data Structure.<p>Hard</p> <p>Design a data structure to store the strings&rsquo; count with the ability to return the strings with minimum and maximum counts.</p> <p>Implement the <code>AllOne</code> class:</p> <ul> <li><code>AllOne()</code> Initializes the object of the data structure.</li> <li><code>inc(String key)</code> Increments the count of the string <code>key</code> by <code>1</code>. If <code>key</code> does not exist in the data structure, insert it with count <code>1</code>.</li> <li><code>dec(String key)</code> Decrements the count of the string <code>key</code> by <code>1</code>. If the count of <code>key</code> is <code>0</code> after the decrement, remove it from the data structure. It is guaranteed that <code>key</code> exists in the data structure before the decrement.</li> <li><code>getMaxKey()</code> Returns one of the keys with the maximal count. If no element exists, return an empty string <code>&quot;&quot;</code>.</li> <li><code>getMinKey()</code> Returns one of the keys with the minimum count. If no element exists, return an empty string <code>&quot;&quot;</code>.</li> </ul> <p><strong>Example 1:</strong></p> <p><strong>Input</strong></p> <pre><code> [&quot;AllOne&quot;, &quot;inc&quot;, &quot;inc&quot;, &quot;getMaxKey&quot;, &quot;getMinKey&quot;, &quot;inc&quot;, &quot;getMaxKey&quot;, &quot;getMinKey&quot;] [ [], [&quot;hello&quot;], [&quot;hello&quot;], [], [], [&quot;leet&quot;], [], []] </code></pre> <p><strong>Output:</strong> [null, null, null, &ldquo;hello&rdquo;, &ldquo;hello&rdquo;, null, &ldquo;hello&rdquo;, &ldquo;leet&rdquo;]</p> <p><strong>Explanation:</strong></p> <pre><code> AllOne allOne = new AllOne(); allOne.inc(&quot;hello&quot;); allOne.inc(&quot;hello&quot;); allOne.getMaxKey(); // return &quot;hello&quot; allOne.getMinKey(); // return &quot;hello&quot; allOne.inc(&quot;leet&quot;); allOne.getMaxKey(); // return &quot;hello&quot; allOne.getMinKey(); // return &quot;leet&quot; </code></pre> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= key.length <= 10</code></li> <li><code>key</code> consists of lowercase English letters.</li> <li>It is guaranteed that for each call to <code>dec</code>, <code>key</code> is existing in the data structure.</li> <li>At most <code>5 * 10⁴</code> calls will be made to <code>inc</code>, <code>dec</code>, <code>getMaxKey</code>, and <code>getMinKey</code>.</li> </ul>

Constructor Summary

Constructors

Constructor	Description
AllOne()

Method Summary

Modifier and Type	Method	Description
void	dec(String key)
String	getMaxKey()
String	getMinKey()
void	inc(String key)

Methods inherited from class java.lang.Object

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

Constructor Details

AllOne

public AllOne()

Method Details

inc

public void inc(String key)

dec

public void dec(String key)

getMaxKey

public String getMaxKey()

getMinKey

public String getMinKey()