Added Swapping Nodes in a Linked List.java

Author: varunu28

Medium/Swapping Nodes in a Linked List.java

@@ -0,0 +1,31 @@
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+  public ListNode swapNodes(ListNode head, int k) {
+    ListNode fast = null;
+    ListNode curr = head;
+    int currCount = 1;
+    while (currCount != k) {
+      curr = curr.next;
+      currCount++;
+    }
+    fast = curr;
+    ListNode slow = head;
+    while (curr.next != null) {
+      slow = slow.next;
+      curr = curr.next;
+    }
+    int temp = fast.val;
+    fast.val = slow.val;
+    slow.val = temp;
+    return head;
+  }
+}