c_cpp 83.从排序列表中删除重复项

Posted 2021-05-14

//Runtime: 12 ms, faster than 93.68% 

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        if(head == nullptr) return nullptr;
        
        ListNode pseudo_head(0);
        pseudo_head.next = head;
        ListNode* prev = pseudo_head.next;
        ListNode* cur = prev->next;
        
        while(cur){
            if(prev->val == cur->val)
                prev->next = cur->next;
            else
                prev = prev->next;
            cur = cur->next;
        }
        
        return pseudo_head.next;
    }
};

//Runtime: 8 ms, faster than 100.00%

class Solution {
public:
    ListNode *deleteDuplicates(ListNode *head) {
        ListNode* cur = head;
        while (cur) {
            while (cur->next && cur->val == cur->next->val)
                cur->next = cur->next->next;
            cur = cur->next;
        }
        return head;
    }
};

//Runtime: 8 ms, faster than 100.00% 

class Solution {
public:
    ListNode* deleteDuplicates(ListNode* head) {
        ListNode* cur = head;
        while(cur && cur->next){
            if(cur->val == cur->next->val){
                ListNode* tmp = cur->next;
                cur->next = cur->next->next;
                delete tmp;
            }
            else
                cur = cur->next;
        }
        return head;
    }
};