Add solution and testcase for 1669 (#157)

* fix: add solution and testcase for 1669

* fix: add solution and testcase for 1669

Author: ashmichheda

src/main/java/com/fishercoder/solutions/_1669.java

@@ -5,6 +5,7 @@
 public class _1669 {
     public static class Solution1 {
         public ListNode mergeInBetween(ListNode list1, int a, int b, ListNode list2) {
+
             ListNode pre = new ListNode(-1);
             ListNode list1Temp = list1;
             pre.next = list1Temp;
@@ -33,4 +34,24 @@ public ListNode mergeInBetween(ListNode list1, int a, int b, ListNode list2) {
             return pre.next;
         }
     }
+    public static class Solution2 {
+        public ListNode mergeInBetween(ListNode list1, int a, int b, ListNode list2) {
+            ListNode endList = list1;
+            ListNode startList = null;
+
+            for (int i = 0; i < b; i++, endList = endList.next) {
+                if (i == a - 1) {
+                    startList = endList;
+                }
+            }
+            // Connect the startList.next to list2
+            startList.next = list2;
+            while (list2.next != null) {
+                list2 = list2.next;
+            }
+            list2.next = endList.next;
+            endList.next = null;
+            return list1;
+        }
+    }
 }

src/test/java/com/fishercoder/_1669Test.java

@@ -2,16 +2,18 @@
 
 import com.fishercoder.common.classes.ListNode;
 import com.fishercoder.common.utils.LinkedListUtils;
-import com.fishercoder.solutions._1;
-import com.fishercoder.solutions._1669;
 import org.junit.BeforeClass;
+import org.junit.Test;import org.junit.BeforeClass;
 import org.junit.Test;
-
-import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
+import com.fishercoder.solutions._1669;
 
 public class _1669Test {
     private static _1669.Solution1 solution1;
+    private static _1669.Solution1 solution2;
+    private static ListNode l1;
+    private static ListNode l2;
+    private static int a;
+    private static int b;
     private static ListNode list1;
     private static ListNode list2;
     private static ListNode expected;
@@ -20,6 +22,7 @@ public class _1669Test {
     @BeforeClass
     public static void setup() {
         solution1 = new _1669.Solution1();
+        solution2 = new _1669.Solution2();
     }
 
     @Test
@@ -31,5 +34,12 @@ public void test1() {
         LinkedListUtils.printList(actual);
         assertEquals(expected, actual);
     }
-
-}
+    @Test
+    public void test2() {
+        l1 = ListNode.createSinglyLinkedList(Arrays.asList(0, 1, 2, 3, 4, 5));
+        l2 = ListNode.createSinglyLinkedList(Arrays.asList(1000000,1000001,1000002));
+        a = 3;
+        b = 4;
+        assertEquals(ListNode.createSinglyLinkedList(Arrays.asList(0,1,2,1000000,1000001,1000002,5)), solution2.mergeInBetween(l1, a, b, l2));
+    }
+}