Update 0004-median-of-two-sorted-arrays.md

Update 0002-Add-Two-Numbers.md

Update 0001-Two-Sum.md

Update 0137-Single-Number-II.md

Update LeetCode第283号问题：移动零.md

添加Java、Python语言支持

添加C++、Java、Python代码实现

Update 0167-Two-Sum-II-Input-array-is-sorted.md

Update LeetCode第20号问题：有效的括号.md

Update 0136-Single-Number.md

添加C、C++、Java、python代码实现

添加Java、Python代码实现

添加Java、Python代码实现

添加Java、python版代码实现

多版本代码实现

update notes 0001-Two-Sum

Solve problem 0189 & 0242

0162 Solved

更新项目

Solved 0120

solved @xiaoshuai96

Solved 0260

Add default return value to Two-Sum solution

0530 solved

替换坏的gif

solved @xiaoshuai96

Solve 0137

695 Solved