[leetcode] Reverse Linked List

[leetcode] Reverse Linked List

문제 링크

Iterative

class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        ListNode *prev = NULL;
        ListNode *cur = head;
        
        while(cur) {
            ListNode *temp = cur->next;
            cur->next = prev;
            prev = cur;
            cur = temp;
        }
        
        return prev;
    }
};

Recursive

class Solution {
public:
    ListNode* reverseList(ListNode* head) {
        if(!head || !head->next) return head;
        
        ListNode *p = reverseList(head->next);
        head->next->next = head;
        head->next = NULL;
        return p;
    }
};