Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring.

Given an input string (s) and a pattern (p), implement wildcard pattern matching with support for '?' and '*'.

1
2

'?' Matches any single character.
'*' Matches any sequence of characters (including the empty sequence).

The matching should cover the entire input string (not partial).

Note:

• s could be empty and contains only lowercase letters a-z.
• p could be empty and contains only lowercase letters a-z, and characters like ? or *.

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.

Write a SQL query for a report that provides the following information for each person in the Person table, regardless if there is an address for each of those people: FirstName, LastName, City, State

Given an input string (s) and a pattern (p), implement regular expression matching with support for '.' and '*'.

1
2

'.' Matches any single character.
'*' Matches zero or more of the preceding element.

The matching should cover the entire input string (not partial).

Note:

• s could be empty and contains only lowercase letters a-z.
• p could be empty and contains only lowercase letters a-z, and characters like . or *.

The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)

1
2
3

P   A   H   N
A P L S I I G
Y   I   R

And then read line by line: "PAHNAPLSIIGYIR"

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

Invert a binary tree.

好久沒寫網誌了，Blogger 已經雜草叢生了（笑）

想當初寫網誌最討厭的一件事情就是排版，我花在排版的時間可能比寫文章還久阿，我都直接用 html 寫了，它排版還是可以跑掉…真是的…

不過這一兩年接觸到了 [Markdown](https://markdown.tw/)，它的語法可以減少不少排版的時間，所以最近又興起了把網誌撿回來的念頭，希望這次可以持之以恆阿…