234.cpp

/**
 * 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) {}
 * };
 */

#include <iostream>
#include <list>
using namespace std;

class Solution {
 public:
  bool isPalindrome(ListNode* head) {
    list<int> list = convert_to_vector(head), rev_list(list);
    rev_list.reverse();
    for (auto it1 = list.begin(), it2 = rev_list.begin(); it1 != list.end();
         it1++, it2++) {
      if (*it1 != *it2) return false;
    }
    return true;
  }

  list<int> convert_to_vector(ListNode* head) {
    list<int> ret;
    while (head) {
      ret.push_back(head->val);
      head = head->next;
    }
    return ret;
  }
};