摘要：
Given a string s and a string t, check if s is subsequence of t. You may assume that there is only lower case English letters in both s and t. t is po 阅读全文
摘要：
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 pro 阅读全文
摘要：
Given a non-negative integer n, count all numbers with unique digits, x, where 0 ≤ x < 10n. Example:Given n = 2, return 91. (The answer should be the 阅读全文