题解 | #删除有序链表中重复的元素-II#

/**
 * struct ListNode {
 *  int val;
 *  struct ListNode *next;
 * };
 */
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 *
 * @param head ListNode类
 * @return ListNode类
 */
struct ListNode* deleteDuplicates(struct ListNode* head ) {
    // write code here
    struct ListNode* res = (struct ListNode*)malloc(sizeof(struct ListNode));
    struct ListNode* node = (struct ListNode*)malloc(sizeof(struct ListNode));
    res->next = NULL;
    node = res;
    while (head != NULL) {
        if (head->next == NULL) {
            struct ListNode* temp = (struct ListNode*)malloc(sizeof(struct ListNode));
            temp->val = head->val;
            temp->next = NULL;
            res->next = temp;
            return node->next;
        }
        if (head->next && head->val != head->next->val) {
            struct ListNode* temp = (struct ListNode*)malloc(sizeof(struct ListNode));
            temp->val = head->val;
            temp->next = NULL;
            res->next = temp;
            res = temp;
            head = head->next;
        }
        if (head->next && head->val == head->next->val) {
            while (head->next && head->val == head->next->val) head = head->next;
            head = head->next;
        }
    }
    return node->next;
}