feat: add 219 Contains Duplicate 2

Author: nphausg

README.md

@@ -36,6 +36,7 @@ Medium: https://medium.com/@nphausg
 | [0027. Remove Element](https://leetcode.com/problems/remove-element)                                               | 🔥     | [Solution](src/com/nphausg/leetcode/easy/RemoveElement.java)              | -                                                                 |
 | [0121. Best time to buy and sell stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock)             | 🔥     | -                                                                         | [Solution](src/com/nphausg/leetcode/easy/BuyAndSellStock.kt)      |
 | [0217. Contains Duplicate](https://leetcode.com/problems/contains-duplicate)                                       | 🔥     | [Solution](src/com/nphausg/leetcode/easy/ContainsDuplicate.java)          | -                                                                 |
+| [0219. Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii)                                 | 🔥     | [Solution](src/com/nphausg/leetcode/easy/ContainsDuplicate2.java)         | -                                                                 |
 | [1929. Concatenation Of Array](https://leetcode.com/problems/concatenation-of-array)                               | 🔥     | [Solution](src/com/nphausg/leetcode/easy/ConcatenationArray.java)         | -                                                                 |
 | [0017. Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number) | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/LetterCombinations.java)       | -                                                                 |
 | [0091. Decode Ways ](https://leetcode.com/problems/decode-ways)                                                    | 🔥🔥   | [Solution](src/com/nphausg/leetcode/medium/DecodeWays.java)               | -                                                                 |

leetcode.solution.iml

@@ -8,5 +8,15 @@
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
+    <orderEntry type="module-library">
+      <library name="JUnit4">
+        <CLASSES>
+          <root url="jar://$MAVEN_REPOSITORY$/junit/junit/4.13.1/junit-4.13.1.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
   </component>
 </module>

src/com/.DS_Store

@@ -0,0 +1,23 @@
+package com.nphausg.leetcode.config;
+
+public class BaseTest {
+    private static int count;
+
+    @org.junit.BeforeClass
+    public static void beforeClass() {
+        System.out.println("Running a test...");
+        System.out.println("This executes before any test cases. Count = " + count++);
+    }
+
+
+    @org.junit.AfterClass
+    public static void afterClass() {
+        System.out.println("This executes after any test cases. Count = " + count++);
+    }
+
+    @org.junit.After
+    public void teardown() {
+        System.out.println("Count = " + count++);
+    }
+
+}

src/com/nphausg/leetcode/Main.java

@@ -0,0 +1,37 @@
+package com.nphausg.leetcode.easy;
+
+import com.nphausg.leetcode.config.BaseTest;
+
+import java.util.HashSet;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * <a href="https://leetcode.com/problems/contains-duplicate-ii">Contains duplicate II</a>
+ */
+public class ContainsDuplicate2 {
+    public static boolean containsNearbyDuplicate(int[] nums, int k) {
+        HashSet<Integer> set = new HashSet<Integer>();
+        for (int i = 0; i < nums.length ; i ++){
+            if(set.contains(nums[i])){
+                return true;
+            }
+            set.add(nums[i]);
+            if(set.size() > k){
+                set.remove(nums [i - k]);
+            }
+        }
+        return false;
+    }
+
+    public static class ContainsDuplicate2Test extends BaseTest {
+
+        @org.junit.Test
+        public void testCases() {
+            //assertTrue(ContainsDuplicate2.containsDuplicate(new int[]{1,0,1,1}, 1));
+            //assertTrue(ContainsDuplicate2.containsDuplicate(new int[]{1, 2, 3, 1}, 3));
+            assertFalse(ContainsDuplicate2.containsNearbyDuplicate(new int[]{1, 2, 3, 1, 2, 3}, 2));
+        }
+    }
+}