删除链表中重复的结点

你快乐吗?

Posted by bbkgl on October 11, 2019

玉颜不及寒鸦色

犹带昭阳日影来

C++,链表题。

对,链表题往往都不难,就是麻烦。。。

其实就是找到连续重复子序列的左右端点,然后删就行了。当然OJ没法判断你删没删,实际上你只要移动指针改变指向就好了哈哈哈。

有个屡试不爽的技巧,就是在原链表前加个头。

详细见代码:

/*
struct ListNode {
    int val;
    struct ListNode *next;
    ListNode(int x) :
        val(x), next(NULL) {
    }
};
*/
class Solution {
public:
    ListNode* deleteDuplication(ListNode* pHead) {
        if (!pHead) return nullptr;
        ListNode *dummy = new ListNode(0);
        dummy->next = pHead;
        ListNode *slow = dummy;
        ListNode *quick = pHead;
        while (quick && quick->next) {
            if (quick->val == quick->next->val) {
                ListNode *p = quick->next;
                while (p && quick->val == p->val) p = p->next;
                delete_node(quick, p);
                quick = p;
                slow->next = quick;
            } else {
                slow = slow->next;
                quick = quick->next;
            }
        }
        return dummy->next;;
    }
    
    void delete_node(ListNode *left, ListNode *right) {
        ListNode *p = left;
        while (p != right) {
            ListNode *q = p->next;
            free(p);
            p = q;
        }
    }
};