题目描述：

Given a pattern and a string str, find if str follows the same pattern.

Examples:

pattern = "abba", str = "dog cat cat dog" should return true.
pattern = "abba", str = "dog cat cat fish ...

题目描述：

According to the Wikipedia's article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathematician John Horton Conway in 1970."

Given a board with m by n cells, each cell ...

1. 备份数据库，然后执行MySQL数据库表变更，SQL如下：

ALTER TABLE `zinnia_entry`
     ADD COLUMN `image_caption` LONGTEXT NULL AFTER `detail_template`,
     ADD COLUMN `lead` LONGTEXT NULL AFTER `image_caption`,
     ADD COLUMN `publication_date` DATETIME NULL AFTER `lead`;

ALTER TABLE `zinnia_entry` ADD INDEX `zinnia_entry_slug_4505cfe2_idx` (`slug`, `publication_date`);

ALTER TABLE `zinnia_entry` ADD ...

题目描述：

Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate element must exist. Assume that there is only one duplicate number, find the duplicate one.

Note ...

题目描述：

Given an Iterator class interface with methods: next() and hasNext(), design and implement a PeekingIterator that support the peek() operation -- it essentially peek() at the element that will be returned by the next call to next().

Here is an ...