/
234.cpp
44 lines (36 loc) · 1014 Bytes
/
234.cpp
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#include <iostream>
// #include <array>
using namespace std;
struct ListNode {
int val;
ListNode* next;
ListNode(int x) : val(x), next(nullptr) {}
};
bool isPalindrome(ListNode* head) {
if (head == nullptr || head->next == nullptr) return true;
ListNode *fast = head, *slow = head, *prev = nullptr, *tmp = nullptr;
while (fast != nullptr && fast->next != nullptr) {
fast = fast->next->next;
//上下部分一定不能交换顺序,否则就会把slow指针后面的都变成nullptr了。
tmp = slow;
slow = slow->next;
tmp->next = prev;
prev = tmp;
}
if (fast != nullptr) {
slow = slow->next;
}
while (slow != nullptr) {
if (slow->val != prev->val) return false;
slow = slow->next;
prev = prev->next;
}
return true;
}
int main() {
ListNode* root = new ListNode(1);
ListNode* next = new ListNode(2);
root->next = next;
cout << isPalindrome(root);
return 0;
}