84

84.删除排序链表中的重复元素

暴力枚举

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */

struct ListNode* deleteDuplicates(struct ListNode* head) {
    struct ListNode *p = head;
    while (p != NULL && p->next != NULL) {
        if (p->next->val == p->val) {
            p->next = p->next->next;
        } else {
            p = p->next;
        }
    }
    return head;
}

思维变换

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     struct ListNode *next;
 * };
 */

struct ListNode* deleteDuplicates(struct ListNode* head) {
    struct ListNode *p = head, *q;
    while (p && p->next) {
        if (p->val - p->next->val) {
            p = p->next;
        } else {
            q = p->next;
            p->next = q->next;
            free(q);
        }
    }
    return head;
}