# Binary search tree after the order traversal sequence

Input an array of integers to determine whether the array is the result of a binary search tree traversal. Return true if yes, false otherwise. Assume that any two digits in the input array are different from each other.

# 7. Data structure (PHP implementation) -- the underlying implementation of the priority queue (heap)

1. Description: it is based on binary tree to achieve 2. Time complexity operation time complexity in queue O(logn) out of queue O(logn)3. The floating operation of the insert node (to put the maximum at the top) (in the code siftUp method) 4. Drop operation on minimum value after eject maximum node (in code siftDown method) 5. Code {code... } 6. Example {code... } {code... }

# LeetCode-144- Preorder traversal of a binary tree

Given the root node of the binary tree, return the pre-order traversal of its node values. See the LeetCode website for an example. The copyright belongs to Lankou Network. Commercial reprint please contact the official authorization, non-commercial reprint please indicate the source.

# It's Design -- Why does MySQL use B+ trees?

I believe that every background development engineer in the interview process, have been asked "MySQL's default storage engine is what? What data structure is a MySQL index?" Questions like this. I believe that everyone who is well prepared can easily answer the question "MySQL's default storage engine is InnoDB and MySQL index uses B+ tree". That's the answer. But why did the programmers who wrote MySQL design it this way?

# Leetcode-112 - Path Sum

Given the root node of the binary tree and an integer targetSum representing the targetSum, determine if there is a path from the root node to the leaf node in the tree. The sum of all the nodes in the path is equal to the target and targetSum. Leaf nodes are nodes that have no children. See the LeetCode website for an example. The copyright belongs to Lankou Network. Commercial reprint please contact the official authorization,...

# LeetCode-111- Minimum depth of a binary tree

Given a binary tree, find its minimum depth. The minimum depth is the number of nodes on the shortest path from the root node to the nearest leaf node. Note: A leaf node is a node that has no children. See the LeetCode website for an example. The copyright belongs to Lankou Network. Commercial reprint please contact the official authorization, non-commercial reprint please indicate the source.

# LeetCode-104- Maximum depth of a binary tree

Given a binary tree, find its maximum depth. The depth of the binary tree is the number of nodes along the longest path from the root node to the furthest leaf node. Note: A leaf node is a node that has no children. See the LeetCode website for an example. The copyright belongs to Lankou Network. Commercial reprint please contact the official authorization, non-commercial reprint please indicate the source.

# Leetcode-101 - Symmetric Binary Trees

Given a binary tree, check if it is mirror symmetric. See the LeetCode website for an example. The copyright belongs to Lankou Network. Commercial reprint please contact the official authorization, non-commercial reprint please indicate the source.

# Leetcode-094 - Intermediate order traversal of a binary tree

Given the root node of a binary tree, return its middle order traversal. See the LeetCode website for an example. The copyright belongs to Lankou Network. Commercial reprint please contact the official authorization, non-commercial reprint please indicate the source.

# LeetCode-100- Same tree

Description: Given the root nodes p and q of two binary trees, write a function to check whether the two trees are the same. Two trees are considered to be the same if they are structurally identical and the nodes have the same value. See the LeetCode website for an example. The copyright belongs to Lankou Network. Commercial reprint please contact the official authorization, non-commercial reprint please indicate the source.

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