Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND of all numbers in this range, inclusive.

Write an algorithm to determine if a number is “happy”.

Given a text file file.txt that contains list of phone numbers (one per line), write a one liner bash script to print all valid phone numbers.

Write a SQL query to find all numbers that appear at least three times consecutively.

Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.

Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique s...

Count the number of prime numbers less than a non-negative number, n.

Given a string of numbers and operators, return all possible results from computing all the different possible ways to group numbers and operators. The valid op...

Given an array of numbers nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find the two elements that appea...