Add DeleteMiddleElement, duplicateElements, find the kth to last node…

… in a linkedlist

src/advance/crackingCodingInterview/ListNode.java

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+package advance.crackingCodingInterview;public class ListNode {
+}

src/advance/crackingCodingInterview/Tests.java

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+package advance.crackingCodingInterview;public class Tests {
+}

src/advance/crackingCodingInterview/linkedList/general/DeleteDuplicates.java

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+package advance.crackingCodingInterview.linkedList.palindromes;
+
+import advance.crackingCodingInterview.ListNode;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class DeleteDuplicates {
+
+    // TC and SC is: O(n)
+    public void deleteDup(ListNode node) {
+        Set<Integer> set=new HashSet<>();
+        ListNode previousNode=null;
+
+        while (node != null){
+            if (set.contains(node.data)){
+                previousNode.next = node.next;
+            }
+            else {
+                set.add(node.data);
+                previousNode = node;
+            }
+            node = node.next;
+        }
+    }
+}

src/advance/crackingCodingInterview/linkedList/general/DeleteMiddle.java

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+package advance.crackingCodingInterview.linkedList.general;public class DeleteMiddle {
+}

src/advance/crackingCodingInterview/linkedList/general/DetectLoopInLinkedList.java

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+package advance.crackingCodingInterview.linkedList.general;public class DetectLoopInLinkedList {
+}

src/advance/crackingCodingInterview/linkedList/general/KthToLast.java

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+package advance.crackingCodingInterview.linkedList.general;public class KthToLast {
+}

src/advance/crackingCodingInterview/linkedList/palindromes/PalindromeRC.java

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+package advance.crackingCodingInterview;
+// Check if the linked list is a palindrome
+
+public class Palindrome {
+
+
+    public boolean isPalindrome(ListNode head) {
+        return false;
+    }
+
+    static boolean isEqual(ListNode firstNode, ListNode secondNode){
+        while (firstNode != null && secondNode != null){
+            if (firstNode.data != secondNode.data){
+                return false;
+            }
+            firstNode = firstNode.next;
+            secondNode  = secondNode.next;
+        }
+        return firstNode == null && secondNode == null;
+    }
+
+    public ListNode reverseAndClone(ListNode node){
+
+    }
+
+
+}

src/advance/crackingCodingInterview/linkedList/palindromes/PalindromeStack.java

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+package advance.crackingCodingInterview.linkedList.palindromes;public class PalindromeStack {
+}

src/advance/linkedlist/LFUCache.java

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+package advance.linkedlist;public class LFUCache {
+}