Recursion selfcontained recursion global variables outside of recursion Recursion Design  Whenever reach to a qualified node, record the node reference and level for that node if meet next qualified node, compare the level, if larger, refresh the glo…

671. 二叉树中第二小的节点 671. Second Minimum Node In a Binary Tree 题目描述 给定一个非空特殊的二叉树,每个节点都是正数,并且每个节点的子节点数量只能为 2 或 0.如果一个节点有两个子节点的话,那么这个节点的值不大于它的子节点的值. 给出这样的一个二叉树,你需要输出所有节点中的第二小的值.如果第二小的值不存在的话,输出 -1. 每日一算法2019/5/12Day 9LeetCode671. Second Minimum Node In a Bin…

problem 671. Second Minimum Node In a Binary Tree 参考 1. Leetcode_easy_671. Second Minimum Node In a Binary Tree; 完…

[leetcode]1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree 链接 leetcode 描述   Given two binary trees original and cloned and given a reference to a node target in the original tree.   The cloned tree is a copy of the original tr…

题目在这里,要求一个二叉树的倒数第二个小的值.二叉树的特点是父节点的值会小于子节点的值,父节点要么没有子节点,要不左右孩子节点都有. 分析一下,根据定义,跟节点的值肯定是二叉树中最小的值,剩下的只需要找到左右子树中比跟节点大的最小值就可以了.对于这个题目,还是考察的二叉树的搜索,第一印象是BFS.使用一个辅助队列存储遍历过程中的节点,遍历过程中,如果节点的值比结果中第二小的值还大,就不用继续把该节点及其所有的子节点入队了,这样可以节省时间.这里的辅助队列使用的是deque,在两端存取数据的复杂度…

Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node in this tree has exactly two or zero sub-node. If the node has two sub-nodes, then this node's value is the smaller value among its two sub-nodes.…

Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node in this tree has exactly two or zero sub-node. If the node has two sub-nodes, then this node's value is the smaller value among its two sub-nodes.…

Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node in this tree has exactly two or zero sub-node. If the node has two sub-nodes, then this node's value is the smaller value among its two sub-nodes.…

这是悦乐书的第285次更新,第302篇原创 01 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第153题(顺位题号是671).给定非空的特殊二叉树,其由具有非负值的节点组成,其中该树中的每个节点具有恰好两个或零个子节点. 如果节点具有两个子节点,则该节点的值是其两个子节点中的较小值.给定这样的二叉树,您需要输出由整个树中所有节点的值组成的集合中的第二个最小值.如果不存在这样的第二个最小值,则输出-1.例如: 2 / \ 2 5 / \ 5 7 输出:5 2 / \ 2 2 输出…

Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node in this tree has exactly two or zero sub-node. If the node has two sub-nodes, then this node's value is the smaller value among its two sub-nodes.…