LeetCode19. Remove Nth Node From End of List

题意

• 删除链表的倒数第n个节点

方法

• dummy node + 遍历

代码

ListNode* removeNthFromEnd(ListNode* head, int n) {
    ListNode* dummy_node = new ListNode(1, head);
    ListNode* tmp_node = head;
    int N = 0;
    while (tmp_node != nullptr) {
        N++;
        tmp_node = tmp_node->next;
    }
    n = N - n + 1;
    cout << n << endl;

    tmp_node = dummy_node;
    ListNode* tmp_next = dummy_node;
    int cnt = 0;
    while (++cnt < n) {
        tmp_next = tmp_next->next;
        tmp_node = tmp_node->next;
    }
    tmp_next = tmp_node->next;
    tmp_node->next = tmp_next->next;

    return dummy_node->next;
}

总结

• 算上栈和双指针的解法, 比较妙的一题, 非常考验基础功力