[Solved] Given the root of an n-ary tree, return the postorder traversal of its nodes’ values. Nary-Tree input serialization is represented in their level order traversal. Each group of children is separated by the null value (See examples)
[Solved] A country is big if: it has an area of at least three million (i.e., 3000000 km2), or it has a population of at least twenty-five million (i.e., 25000000). Write an SQL query to report the name, population, and area of the big countries.
[Solved] Given the root of an n-ary tree, return the preorder traversal of its nodes’ values. Nary-Tree input serialization is represented in their level order traversal. Each group of children is separated by the null value (See examples)
[Solved] In MATLAB, there is a handy function called reshape which can reshape an m x n matrix into a new one with a different size r x c keeping its original data. You are given an m x n matrix mat and two integers r and c representing the number of rows and the number of columns of the wanted reshaped matrix.
[Solved] Given an integer array nums of 2n integers, group these integers into n pairs (a1, b1), (a2, b2), …, (an, bn) such that the sum of min(ai, bi) for all i is maximized. Return the maximized sum.
[Solved] Given a n-ary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
[Solved] Given a string s, reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.
[Solved] We define the usage of capitals in a word to be right when one of the following cases holds: All letters in this word are capitals, like “USA”. All letters in this word are not capitals, like “leetcode”. Only the first letter in this word is capital, like “Google”.
[Solved] Given a string s, find the longest palindromic subsequence’s length in s. A subsequence is a sequence that can be derived from another sequence by deleting some or no elements without changing the order of the remaining elements.