Given two arrays, write a function to compute their intersection.
Find the sum of all left leaves in a given binary tree.
Given an arbitrary ransom note string and another string containing letters from all the magazines
Given an array nums, write a function to move all 0’s to the end of it while maintaining the relative order of the non-zero elements.
Invert a binary tree.
Given a non-negative integer num, repeatedly add all its digits until the result has only one digit.
Given a binary tree, find its maximum depth.
Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.
Given an array of integers, every element appears twice except for one. Find that single one.
You are playing the following Nim Game with your friend: