摘要：
Given an integer matrix, find the length of the longest increasing path. From each cell, you can either move to four directions: left, right, up or do 阅读全文
摘要：
Given a nested list of integers, implement an iterator to flatten it. Each element is either an integer, or a list -- whose elements may also be integ 阅读全文
摘要：
Find the length of the longest substring T of a given string (consists of lowercase letters only) such that every character in T appears no less than 阅读全文