Added Acconts Merge program with Disjont set in Graphs section

Author: karthik124a

src/main/java/com/thealgorithms/graph/DisjointSet.java

@@ -153,27 +153,4 @@ public List<List<String>> accountsMerge(List<List<String>> accountList) {
 
         return mergedAccounts;
     }
-
-}
-
-/** 
- * 
- * this the program for testing the above algorithm
- * 
-public class DisjointSetMain {
-    public static void main(String[] args) {
-        List<List<String>> list = new ArrayList<>();
-        list.add(new ArrayList<>(List.of("abc", "[email protected]","[email protected]")));
-        list.add(new ArrayList<>(List.of("abc","[email protected]","[email protected]")));
-        list.add(new ArrayList<>(List.of("Mary","[email protected]")));
-        list.add(new ArrayList<>(List.of("John","[email protected]")));
-        list.add(new ArrayList<>(List.of("John", "[email protected]", "[email protected]")));
-        DisjointSet ds = new DisjointSet(list.size());
-        List<List<String>> ans = ds.accountsMerge(list);
-        for(List<String> val : ans){
-            System.out.println(val);
-        }
-    }
-}
-
-*/
+}

src/test/java/com/thealgorithms/graph/DisjointSetTest.java

@@ -0,0 +1,52 @@
+package com.thealgorithms.graph;
+
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import java.util.*;
+
+public class DisjointSetTest {
+
+    @Test
+    public void testAccountsMerge() {
+        // Input data setup
+        List<List<String>> list = new ArrayList<>();
+        list.add(new ArrayList<>(List.of("abc", "[email protected]", "[email protected]")));
+        list.add(new ArrayList<>(List.of("abc", "[email protected]", "[email protected]")));
+        list.add(new ArrayList<>(List.of("Mary", "[email protected]")));
+        list.add(new ArrayList<>(List.of("John", "[email protected]")));
+        list.add(new ArrayList<>(List.of("John", "[email protected]", "[email protected]")));
+
+        // Create instance of your Solution/DisjointSet class
+        DisjointSet disjointSet = new DisjointSet(list.size());  // or DisjointSet if that’s where accountsMerge() lives
+
+        // Execute the method
+        List<List<String>> result = disjointSet.accountsMerge(list);
+
+        // Expected output (order of accounts may vary)
+        List<List<String>> expected = new ArrayList<>();
+        expected.add(Arrays.asList("abc", "[email protected]", "[email protected]", "[email protected]"));
+        expected.add(Arrays.asList("Mary", "[email protected]"));
+        expected.add(Arrays.asList("John", "[email protected]", "[email protected]"));
+
+        // Sort both results for deterministic comparison
+        sortAccounts(result);
+        sortAccounts(expected);
+
+        // Verify results
+        assertEquals(expected, result);
+    }
+
+    // Helper method to sort emails and accounts for deterministic comparison
+    private static void sortAccounts(List<List<String>> accounts) {
+        for (List<String> acc : accounts) {
+            // Sort all emails (leave name first)
+            List<String> emails = acc.subList(1, acc.size());
+            Collections.sort(emails);
+        }
+        // Sort accounts lexicographically by name
+        accounts.sort(Comparator.comparing(a -> a.get(0)));
+    }
+}
+
+