chore(CPlusPlus): add palindrome-linked-list

algorithms/CPlusPlus/Linked-Lists/palindrome-linked-list.cpp

@@ -0,0 +1,80 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+// TC = O(N)
+// SC = O(1)
+
+// Given the head of a singly linked list, return true if it is a palindrome
+// or false otherwise.
+
+// Example 1:
+// Input: head = [1,2,2,1]
+// Output: true
+
+// Example 2:
+// Input: head = [1,2]
+// Output: false
+
+
+// Definition for singly-linked list.
+
+struct ListNode {
+    int val;
+    ListNode* next;
+    ListNode(int x) : val(x), next(NULL) {}
+};
+
+class Solution {
+public:
+    bool isPalindrome(ListNode* head) {
+        if (head == NULL || head->next == NULL) return true;
+
+        vector<int> ans;
+        ListNode* temp = head;
+        while (temp) {
+            ans.push_back(temp->val);
+            temp = temp->next;
+        }
+
+        int i = 0;
+        int j = ans.size() - 1;
+        while (i < j) {
+            if (ans[i] != ans[j]) return false;
+            i++;
+            j--;
+        }
+
+        return true;
+    }
+};
+
+int main() {
+    // Create a sample linked list
+    ListNode* head = new ListNode(1);
+    ListNode* node2 = new ListNode(2);
+    ListNode* node3 = new ListNode(3);
+    ListNode* node4 = new ListNode(2);
+    ListNode* node5 = new ListNode(1);
+
+    head->next = node2;
+    node2->next = node3;
+    node3->next = node4;
+    node4->next = node5;
+
+    // Create an instance of the Solution class
+    Solution solution;
+
+    // Call the isPalindrome function and print the result
+    bool isPalin = solution.isPalindrome(head);
+    cout << "Is the linked list a palindrome? " << (isPalin ? "Yes" : "No") << endl;
+
+    // Clean up the linked list memory
+    ListNode* temp = head;
+    while (temp) {
+        ListNode* nextNode = temp->next;
+        delete temp;
+        temp = nextNode;
+    }
+
+    return 0;
+}