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Logistic Regression

Written by  on October 6, 2018

逻辑斯谛回归因为其易于实现,可解释性强,已经成为了工业界应用最广泛的机器学习算法。这篇文章主要讨论的是二项逻辑斯谛回归 (binominal logistic regression),以下简称LR。

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素描心得

Written by  on August 18, 2018

去年国庆的时候的在798里面的一个画室里面报了一个素描班,上个星期终于把两期课程学完了,总共画了二十多节课,从一开始的不知所措,到最后多少可以的画的有模有样,也算是没有白上,今天想着还是总结一下心得比较好,便于后面继续自学进步。

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POJ3020

Written by  on August 14, 2018

POJ3020 Antenna Placement Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 10821 Accepted: 5324 Description The Global Aerial Research Centre has been allotted the task of building the fifth generation of mobile phone nets in Sweden. The most striking reason why they got the job, is their discovery of a new, highly noise resistant, antenna. It is called 4DAir, and comes in four types. Each type can only transmit and receive signals in a direction aligned with a (slightly skewed) latitudinal and longitudinal grid, because of the interacting electromagnetic field of the earth. The four types correspond to antennas operating in the directions north, west, south, and east, respectively. Below is an example picture of places of interest, depicted by twelve small rings, and nine 4DAir antennas depicted by ellipses covering them.

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POJ3041

Written by  on August 14, 2018

POJ3041 Asteroids Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 26141 Accepted: 14134 Description Bessie wants to navigate her spaceship through a dangerous asteroid field in the shape of an N x N grid (1 <= N <= 500). The grid contains K asteroids (1 <= K <= 10,000), which are conveniently located at the lattice points of the grid.

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Codeforces #879C

Written by  on November 6, 2017

879C C. Short Program time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Petya learned a new programming language CALPAS. A program in this language always takes one non-negative integer and returns one non-negative integer as well.

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奇异值分解

Written by  on February 23, 2017

在自然语言处理或者机器学习相关应用时,通常首先要做的是将每一个样本转换成一个向量,然后将预处理过后的样本聚集在一起以矩阵计算的形式来对数据进行分析,然而很多时候都会碰到向量维度过高矩阵过大带来的计算复杂度太高问题,这个时候就要对样本数据集进行降维处理,也就是通常所说的主成分分析 (Principal components analysis,PCA),在尽可能保持原本数据集的特征的前提下降低数据集维度,简单的线性回归就是一种降维操作(将二维平面上的点用一维的线段来表示)。

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POJ1182

Written by  on December 13, 2016

POJ1182 食物链 Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 66244 Accepted: 19522 Description 动物王国中有三类动物A,B,C,这三类动物的食物链构成了有趣的环形。A吃B, B吃C,C吃A。

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Codeforces #733 D

Written by  on November 2, 2016

733D D. Kostya the Sculptor time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output Kostya is a genial sculptor, he has an idea: to carve a marble sculpture in the shape of a sphere. Kostya has a friend Zahar who works at a career. Zahar knows about Kostya’s idea and wants to present him a rectangular parallelepiped of marble from which he can carve the sphere.

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Codeforces #719 C

Written by  on October 26, 2016

719C C. Efim and Strange Grade time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output

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Codeforces #721 C

Written by  on October 11, 2016

721C C. Journey time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output Recently Irina arrived to one of the most famous cities of Berland — the Berlatov city. There are n showplaces in the city, numbered from1 to n, and some of them are connected by one-directional roads. The roads in Berlatov are designed in a way such that there are nocyclic routes between showplaces.

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