LeetCode刷题笔记- 143.翻转链表

暴力解法

c代码注意点 题目

void reorderList(struct ListNode* head){
    struct ListNode *dummy = NULL, *t = NULL, *p = NULL;
    dummy = head;
    if (dummy == NULL
         || dummy->next == NULL)
    {
        return head;
    }
    while(dummy != NULL) {
            t = dummy;
            do {
                p = t;
                t = t->next;
            } while(t != NULL && t->next != NULL);
            //t == NULL or t->next == NULL
            if(t == NULL)
                break;
            p->next = NULL;
            t->next = dummy->next;
            dummy->next = t;
            dummy = t->next;
    }
    return head;
}

链子节点p,t注意每次都需要初始化，如代码中由原来的while()循环修改为do{...}while()循环；暴力解法耗时680ms，待优化；