只有把一个语言中的常用函数了如指掌了，才能在处理问题的过程中得心应手，快速地找到最优方案。

作用： 把迭代器中相邻的元素按照key函数分组，当key=None时，把相邻的重复元素进行分组。

List comprehensions can also be used with conditionals. For example, let's say y...

Given two integers n and k, return all possible combinations of k numbers out of...

Given a string containing only digits, restore it by returning all possible vali...

Given n pairs of parentheses, write a function to generate all combinations of w...

Find all possible combinations of k numbers that add up to a number n, given tha...

Given two integers n and k, return all possible combinations of k numbers out of...

Given a set of candidate numbers (C) (without duplicates) and a target number (T...

Given a collection of candidate numbers (C) and a target number (T), find all un...

Given n pairs of parentheses, write a function to generate all combinations of w...

Given a digit string, return all possible letter combinations that the number co...

Given two integers n and k, return all possible combinations of k numbers out of...

Given a set of candidate numbers (candidates) (without duplicates) and a target ...

Find all possible combinations of k numbers that add up to a number n, given tha...

Given n pairs of parentheses, write a function to generate all combinations of w...

来了来了，终于来了！上篇文章我们实现了方块的生成和交换，那本篇文章就到了该系列的重头戏，我们一起来实现消消乐的消除算法！

Avoid errors. Readability. Not everyone has the operator table memorized.

意思说 给你一组正数C，然后 给你一个目标数T， 让你从那组C中找到加在一起等于T的那些组合。 比如 给你7 然后 从[2,3,6,7]中可以找到[2,2,...

permutations/combinations/combinations_with_replacement