Write a program to check whether a given number is an ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. ...

Write a program to find the nth super ugly number. Super ugly numbers are positive numbers whose all prime factors are in the given prime list ...

An ugly number is a positive integer that is divisible by a, b, or c. Given four integers n, a, b, and c, return the nth ugly number. Example ...

Write a program to find the n-th ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example ...

A strobogrammatic number is a number that looks the same when rotated 180 degrees (looked at upside down). Find all strobogrammatic numbers ...

We can rotate digits by 180 degrees to form new digits. When 0, 1, 6, 8, 9 are rotated 180 degrees ...

Given a non-empty array of integers, every element appears three times except for one, which appe ...

A 2d grid map of m rows and n columns is initially filled with water. We may perform an addLand o ...