1 files changed, 48 insertions, 0 deletions

diff --git a/top-interview-questions/easy/linked_list/05_palindrome_linked_list.cc b/top-interview-questions/easy/linked_list/05_palindrome_linked_list.cc
new file mode 100644
index 0000000..3f42e4a
--- /dev/null
+++ b/top-interview-questions/easy/linked_list/05_palindrome_linked_list.cc
@@ -0,0 +1,48 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode() : val(0), next(nullptr) {}
+ *     ListNode(int x) : val(x), next(nullptr) {}
+ *     ListNode(int x, ListNode *next) : val(x), next(next) {}
+ * };
+ */
+class Solution {
+public:
+    // Copy the list.
+    ListNode* clone(const ListNode* node) {
+        if (!node) return nullptr;
+        ListNode* copy = new ListNode();
+        copy->val = node->val;
+        if (node->next) {
+            copy->next = clone(node->next);
+        } else {
+            copy->next = nullptr;
+        }
+        return copy;
+    }
+
+    // Reverse a list and return the new of the reversed list.
+    ListNode* reverse(ListNode* node) {
+        if (!node)       return nullptr;
+        if (!node->next) return node;
+        ListNode* head = reverse(node->next);
+        node->next->next = node;
+        node->next = nullptr;
+        return head;
+    }
+
+    // Compare two lists for equality.
+    bool eq(const ListNode* a, const LideNode* b) {
+        if (!a && !b)         return true;
+        if (!a)               return false;
+        if (!b)               return false;
+        if (a->val != b->val) return false;
+        return eq(a->next, b->next);
+    }
+
+    bool isPalindrome(ListNode* head) {
+        return eq(head, reverse(clone(head)));
+    }
+};