add sort test

Author: yennj12

leetcode_java/pom.xml

@@ -20,6 +20,28 @@
             <version>21.0.1</version>
         </dependency>
 
+        <!-- UT -->
+        <!-- JUnit 5 (JUnit Jupiter) dependency for unit testing -->
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>5.8.2</version> <!-- Use the latest version here -->
+            <scope>test</scope>
+
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>5.8.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>RELEASE</version>
+            <scope>compile</scope>
+        </dependency>
+
     </dependencies>
 
     <build>

leetcode_java/src/main/java/dev/Sorting/ArraySortTest.java

@@ -0,0 +1,4 @@
+package dev.Sorting;
+
+public class ArraySortTest {
+}

leetcode_java/src/main/java/dev/Sorting/HashMapSortTest.java

@@ -0,0 +1,66 @@
+package dev.Sorting;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.sql.Array;
+import java.util.*;
+
+public class HashMapSortTest {
+
+//    @Before
+//    public void init(){
+//
+//    }
+
+
+    @Test
+    public void testSortMapWithValue(){
+
+        // ------------------- TEST 6 : sort map on val, key len
+        Map<String, Integer> map = new HashMap<>();
+        map.put("apple", 3);
+        map.put("banana", 2);
+        map.put("lem", 3);
+        map.put("kiwi", 5);
+        map.put("peachhh", 3);
+
+        System.out.println("Original map: " + map);
+
+        /**
+         *  Note !!!
+         *
+         *   difference between below:
+         *
+         *
+         * 1)  List<Set<String>> keys = Arrays.asList(map.keySet());
+         *     In this line, you're using Arrays.asList() to wrap map.keySet() into a list.
+         *     map.keySet() returns a Set<String>, which is a set of the map's keys.
+         *     - Arrays.asList() takes an array (or a list of elements)
+         *       and converts it into a fixed-size list. When you pass a single Set to Arrays.asList(),
+         *       it wraps this single Set<String> into a list.
+         *
+         * 2) Arrays.asList() takes an array (or a list of elements)
+         *    and converts it into a fixed-size list. When you pass a single Set
+         *    to Arrays.asList(), it wraps this single Set<String> into a list.
+         *   -> So, keys will be a List<Set<String>> where the list contains a single Set<String>, which is the set of keys from the map.
+         *
+         */
+        //List<Set<String>> keys = Arrays.asList(map.keySet());
+        ArrayList<String> keyList = new ArrayList<>(map.keySet());
+        System.out.println(">>> (before sort) keyList = " + keyList);
+
+        Collections.sort(keyList, (x,y) -> {
+            // compare val, bigger first (decreasing order)
+            int valDiff = map.get(y) - map.get(x);
+            if (valDiff == 0){
+                // compare key len, shorter first (increasing order)
+                return x.length() - y.length();
+            }
+            return valDiff;
+        });
+
+        System.out.println(">>> (after sort) keyList = " + keyList);
+    }
+
+}

leetcode_java/src/main/java/dev/Sorting/ListSortTest.java

@@ -0,0 +1,4 @@
+package dev.Sorting;
+
+public class ListSortTest {
+}