摘要： John got a full mark on PAT. He was so happy that he decided to hold a raffle（抽奖） for his followers on Weibo -- that is, he would select winners from 阅读全文

摘要： On a broken keyboard, some of the keys are always stucked. So when you type some sentences, the characters corresponding to those keys will appear rep 阅读全文

摘要： //本学习笔记只是记录，并未有深入思考。 1.什么是数据挖掘？ 数据挖掘是数据库中发现必不可少的一部分。 数据预处理主要包括（可能是最耗时的步骤）： 1.融合来自多个数据源的数据 2.清洗数据以消除噪声和重复的观测值 3.选择与当前数据挖掘任务相关的记录和特征。 2.数据挖掘要解决的问题 1.可伸缩 阅读全文

摘要： Forbes magazine publishes every year its list of billionaires based on the annual ranking of the world's wealthiest people. Now you are supposed to si 阅读全文

摘要： Unlike in nowadays, the way that boys and girls expressing their feelings of love was quite subtle in the early years. When a boy A had a crush on a g 阅读全文

摘要： This time your job is to fill a sequence of N positive integers into a spiral matrix in non-increasing order. A spiral matrix is filled in from the fi 阅读全文

摘要： 2. Missing number 转自：https://mp.weixin.qq.com/s/WLRXLdi-3igkjtiWlHg7Ug Given a positive integer n(n≤40), pick n-1 numbers randomly from 1 to n and con 阅读全文

摘要： For two rational numbers, your task is to implement the basic arithmetics, that is, to calculate their sum, difference, product and quotient. Input Sp 阅读全文

摘要： Given three integers A, B and C in [−2​63​​,2​63​​], you are supposed to tell whether A+B>C. Input Specification: The first line of the input gives th 阅读全文

摘要： 转自：https://blog.csdn.net/bitcarmanlee/article/details/51589143 在一篇博客中看到单变量线性回归可以使用最小二乘或者递归下降来求解，最小二乘就是最小化平方误差，解决最优化问题。 但是对其具体的过程还不是很理解，所以来总结学习一下。 1.最小 阅读全文