c_cpp 234.回文链接清单

Posted 2021-05-14

//20ms  50%

class Solution {
public:
    bool isPalindrome(ListNode* head) {
        if(!head || !head->next)
            return true;
        vector<int> array;
        array.push_back(head->val);
        while(head->next != NULL){
            head = head->next;
            array.push_back(head->val);
        }
        // cout << array.size();
        for(int i = 0,j = array.size()-1;i < j;++i,--j)
            if(array[i] != array[j])
                return false;
        return true;
    }
};

//20 ms 

class Solution {
public:
    ListNode* temp;
    bool isPalindrome(ListNode* head) {
        temp = head;
        return check(head);
    }
    
    bool check(ListNode* p){
        if(NULL == p) return true;
        bool isPal = check(p->next) & (temp->val == p->val);
        temp = temp->next;
        return isPal;
    }
};