Nine notes

Given a range of consecutive IP, return the least amount of CIDR IPs needed

Design a hit counter which counts the number of hits received in the past 5 minutes.

Given an integer (signed 32 bits), write a function to check whether it is a power of 4.

Given an integer, write a function to determine if it is a power of two.

Write a program that outputs the string representation of numbers from 1 to n.

Given two non-negative numbers num1 and num2 represented as string, return the sum of num1 and num2.

Given two 1d vectors, implement an iterator to return their elements alternately.

Given a nested list of integers, implement an iterator to flatten it.

Given an array of words and a length L, format the text such that each line has exactly L characters and is fully (left and right) justified.

Implement a basic calculator to evaluate a simple expression string.