摘要： 题目： Description: Count the number of prime numbers less than a non-negative number, n. Credits:Special thanks to @mithmatt for adding this problem and 阅读全文

摘要： 题目： Remove all elements from a linked list of integers that have value val. ExampleGiven: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6Return: 1 --> 阅读全文

摘要： 题目： Write an algorithm to determine if a number is "happy". A happy number is a number defined by the following process: Starting with any positive in 阅读全文