Last semester I had 4 classes and really had no time to update my blog.

Now in the summer break, I finally have time to summary.

Notes for sorting algorithm

Description

Given a string S of ‘(‘ and ‘)’ parentheses, we add the minimum number of parentheses ( ‘(‘ or ‘)’, and in any positions ) so that the resulting parentheses string is valid.

Formally, a parentheses string is valid if and only if:

It is the empty string, or
It can be written as AB (A concatenated with B), where A and B are valid strings, or
It can be written as (A), where A is a valid string.
Given a parentheses string, return the minimum number of parentheses we must add to make the resulting string valid.

Description

Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999.

detail

Description

Given a 32-bit signed integer, reverse digits of an integer.
Note:
Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−2^31, 2^31 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

record some skills using jupyter.

description

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

You may assume that each input would have exactly one solution, and you may not use the same element twice.

刷谷歌框架

参考:
努比亚z17安装谷歌框架

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