Given the root of a binary tree, return the average value of the nodes on each level in the form of an array. Answers within 10-5 of the actual answer will be accepted. Example 1: Input: root = [...

Given the root of a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. Example 1: Input: root = [1,2,3,null,5,n...

Given the root of a binary tree, return the bottom-up level order traversal of its nodes’ values. (i.e., from left to right, level by level from leaf to root). Example 1: Input: root = [3,9,20,nu...

Given the root of a binary tree, return the level order traversal of its nodes’ values. (i.e., from left to right, level by level). Example 1: Input: root = [3,9,20,null,null,15,7] Output: [[3],[...

参考内容：代码随想录 1.递归算法的三个要素。 每次写递归，都按照这三要素来写，可以保证大家写出正确的递归算法！ 确定递归函数的参数和返回值： 确定哪些参数是递归的过程中需要处理的，那么就在递归函数里加上这个参数， 并且还要明确每次递归的返回值是什么进而确定递归函数的返回类型。 确定终止条件： 写完了递归算法, 运行的时候，经常会遇到栈溢出的错误，就是...

Given the root of a binary tree, return the postorder traversal of its nodes’ values. Example 1: Input: root = [1,null,2,3] Output: [3,2,1] Explanation: Example 2: Input: root = [1,2,3,4,5,nu...

Given the root of a binary tree, return the inorder traversal of its nodes’ values. Example 1: Input: root = [1,null,2,3] Output: [1,3,2] Explanation: Example 2: Input: root = [1,2,3,4,5,null...

Given the root of a binary tree, return the preorder traversal of its nodes’ values. Example 1: Input: root = [1,null,2,3] Output: [1,2,3] Explanation: Example 2: Input: root = [1,2,3,4,5,nul...

Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order. Example 1: Input: nums = [1,1,1,2,2,3], k = 2 Output: [1,2] Example 2: ...

MISCADA – computer vision Workshop 7 Using the pygame library, the following video clip can be generated Step1: Identification Before being able to track the ball, we must identify it T...