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

Given a positive integer n, break it into the sum of at least two positive integers and maximize the product of those integers. Return the maximum product you c...

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

Given an integer array nums, return the number of range sums that lie in [lower, upper] inclusive.Range sum S(i, j) is defined as the sum of the elements in nu...

Given an integer matrix, find the length of the longest increasing path.

Given a sorted positive integer array nums and an integer n, add/patch elements to the array such that any number in range [1, n] inclusive can be formed by the...

Given a non-empty 2D matrix matrix and an integer k, find the max sum of a rectangle in the matrix such that its sum is no larger than k.

Write a program to find the nth super ugly number.

Andrew has just made a breakthrough in sociology: he realized how to predict whether two persons will be good friends or not. It turns out that each person has ...

Find all pairs of prime numbers (A, B) such that A<=B and their sum is also a prime number and does not exceed N.