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原创概率论与数理统计学习笔记

第一章随机事件与概率第二章随机变量及其分布第三章多维随机变量及其分布第四章大数定律与中心极限定理第五章统计量及其分布第六章参数估计第七章假设检验第八章方差分析与回归分析第一章随机事件与概率1.1 随机事件及其运算概率论与数理统计研究的对象是随机现象. 概率论是研究随机现象的模型（即概率分布），数理统计是研究随机现象的数据收集与处理。随机现象：在一定的条件下，并不

2017-02-16 14:48:02 2013

原创【深度学习】读书笔记壹深度学习概述

深度学习的前世今生。前言概念AI深度学习：层次化的概念让计算机构建较简单的概念来学习复杂概念。如果绘制出这些概念如何建立在彼此之上的图，我们将得到一张“深”（层次很多）的图。出于这个原因，我们称这种方法为AI深度学习。知识图谱(knowledge base)方法: 计算机可以通过这些形式化语言自动地使用逻辑推理规则来理解声明。机器学习(machine learning): Al系统需要具备自己获

2017-02-09 21:10:02 740

原创概率论与数理统计学习笔记

第一章随机事件与概率第二章随机变量及其分布第三章多维随机变量及其分布第四章大数定律与中心极限定理第五章统计量及其分布第六章参数估计第七章假设检验第八章方差分析与回归分析第一章随机事件与概率1.1随机事件及其运算概率论与数理统计研究的对象是随机现象. 概率论是研究随机现象的模型（即概率分布），数理统计是研究随机现象的数据收集与处理

2016-05-06 23:03:56 7698 1

原创链表的反转问题(Reverse Linked List)

反转单链表思路有三种，1.将1->2->3变为

2015-07-30 10:17:19 957

原创 KSum问题

KSum是Leetcode上的一系列问题，本质上还是hash问题。现在从最基本的2Sum开始拓展到KSum.Two Sum Total Accepted: 112324 Total Submissions: 635568Given an array of integers, find two numbers such that they add up to a

2015-07-20 16:55:46 810

原创八皇后问题和数独问题

八皇后问题和数独问题是经典dfs+回溯的问题，其中还可以涉及hash，是非常好的练习题目。我们以leetcode中的四道题目为例。Valid Sudoku Total Accepted: 40598 Total Submissions: 149092 Determine if a Sudoku is validThe Sudoku board c

2015-07-18 09:13:58 1203

原创 Happy Number

1. 题目Write an algorithm to determine if a number is “happy”.A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of th

2015-07-17 10:00:19 465

原创不要被阶乘吓到

1.给定整数N,那么N的阶乘N!末尾有多少个0?这个问题经过质因子分解转换为求5的指数ret = 0;for(i = 1; i <= N ; i++) { j = i; while (j % 5 == 0) { ret++; j /=5; }}[N/k] 等于1,2,3...,N中能被k整除的数的个数

2015-04-26 13:52:23 583

原创求二进制数中1的个数

这道题我一开始能想到的就只有位运算+右移，最直观。二进制最后一位对应于mod2,右移一位对应于/2int count(int v) { int num = 0; while(v) { if(v % 2 == 1) { num++; } v /= 2; } return num;}in

2015-04-24 19:25:19 474

原创 Surrounded Regions

Surrounded RegionsGiven a 2D board containing 'X' and 'O', capture all regions surrounded by 'X'.A region is captured by flipping all 'O's into 'X's in that surrounded region.For exa

2015-04-23 11:01:35 519

原创 Word Ladder

Word LadderGiven two words (beginWord and endWord), and a dictionary, find the length of shortest transformation sequence from beginWord to endWord, such that:Only one letter can be ch

2015-04-22 09:49:58 1379

原创 2015编程之美资格赛题目3 : 基站选址

描述需要在一个N × M的网格中建立一个通讯基站，通讯基站仅必须建立在格点上。网格中有A个用户，每个用户的通讯代价是用户到基站欧几里得距离的平方。网格中还有B个通讯公司，维护基站的代价是基站到最近的一个通讯公司的路程（路程定义为曼哈顿距离）。在网格中建立基站的总代价是用户通讯代价的总和加上维护基站的代价，最小总代价。输入第一行为一个整数T，表示数据组数。每组数据第一

2015-04-21 15:15:04 843

原创 2015编程之美资格赛题目2 : 回文字符序列

描述给定字符串，求它的回文子序列个数。回文子序列反转字符顺序后仍然与原序列相同。例如字符串aba中，回文子序列为"a", "a", "aa", "b", "aba"，共5个。内容相同位置不同的子序列算不同的子序列。输入第一行一个整数T，表示数据组数。之后是T组数据，每组数据为一行字符串。输出对于每组数据输出一行，格式为"Case #X: Y"，X代表数据编号（从1开始）

2015-04-21 11:40:51 666

原创 2015编程之美资格赛题目1 : 2月29日

描述给定两个日期，计算这两个日期之间有多少个2月29日（包括起始日期）。只有闰年有2月29日，满足以下一个条件的年份为闰年：1. 年份能被4整除但不能被100整除2. 年份能被400整除输入第一行为一个整数T，表示数据组数。之后每组数据包含两行。每一行格式为"month day, year"，表示一个日期。month为{"January", "February",

2015-04-21 11:28:46 746

原创 Palindrome Partitioning II

Palindrome Partitioning IIGiven a string s, partition s such that every substring of the partition is a palindrome.Return the minimum cuts needed for a palindrome partitioning of s

2015-04-14 11:01:12 536

原创 Palindrome Partitioning

Palindrome PartitioningGiven a string s, partition s such that every substring of the partition is a palindrome.Return all possible palindrome partitioning of s.For example, given

2015-04-14 11:00:48 374

原创 Triangle

TriangleGiven a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.For example, given the following triangle[

2015-04-14 09:33:18 417

原创 Search a 2D Matrix

Search a 2D MatrixWrite an efficient algorithm that searches for a value in anm x n matrix. This matrix has the following properties:Integers in each row are sorted from left t

2015-04-11 10:19:58 405

原创 Search for a Range

Search for a RangeGiven a sorted array of integers, find the starting and ending position of a given target value.Your algorithm's runtime complexity must be in the order of O(log

2015-04-10 15:34:19 490

原创 First Missing Positive

First Missing PositiveGiven an unsorted integer array, find the first missing positive integer.For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2.Your algorithm should run in

2015-04-09 17:13:44 446

原创 Insertion Sort List

Insertion Sort List Sort a linked list using insertion sort.很简单的一道题，思路跟数组的插入排序一样/** * Definition for singly-linked list. * struct ListNode { * int val; * Li

2015-04-09 11:26:52 356

原创 Merge k Sorted Lists

Merge k Sorted ListsMerge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity./** * Definition for singly-linked list. * struct ListNode { *

2015-04-09 09:35:35 311

原创 Merge Two Sorted Lists

Merge Two Sorted ListsMerge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists./**

2015-04-08 21:59:17 396

原创 Merge Sorted Array

Merge Sorted ArrayGiven two sorted integer arrays A and B, merge B into A as one sorted array.Note:You may assume that A has enough space (size that is greater or equal to m + n) to hold a

2015-04-08 21:52:41 401

原创 Sum Root to Leaf Numbers

Sum Root to Leaf NumbersGiven a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.An example is the root-to-leaf path 1->2->3 which rep

2015-04-04 21:25:38 327

原创 Remove Duplicates from Sorted Array II

Remove Duplicates from Sorted Array IIFollow up for "Remove Duplicates":What if duplicates are allowed at most twice?For example,Given sorted array A = [1,1,1,2,2,3],Your f

2015-03-25 21:20:32 380

原创 Remove Duplicates from Sorted Array

Remove Duplicates from Sorted ArrayGiven a sorted array, remove the duplicates in place such that each element appear only once and return the new length.Do not allocate extra space for anot

2015-03-25 16:10:10 376

原创 Binary Tree Preorder Traversal

Binary Tree Preorder Traversal Given a binary tree, return the preorder traversal of its nodes' values.For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3return [1,2,3].递归版本/** * Definit

2015-03-24 17:04:43 328

原创深度学习基础（七）Self-Taught Learning to Deep Networks

有了自学算法去提取特征，我们可以进一步扩展模型这个模型是在特征模型的基础上多了一步分类器，这个分类器的引入使得我们可以进一步调整参数。微调（fine-tune）指的的是通过输入有标记的再通过牛顿下降法来调整参数从而减小训练误差什么时候可以使用微调呢？当然是有大量的有标记样本啦。上面这个模型试简单的三层神经网络因为每一个隐层代表了对前一层的一次非线性变换，简单的三层模

2015-03-20 21:27:26 745

原创深度学习基础（六）Self-Taught Learning

要想提高学习类的算法，最简单的方法就是使用更多的数据，但是有标签的数据往往是很难获取的，因此对于无标签的数据的学习，我们有自学习算法和无监督特学习算法。有两类常用的特征学习算法，自学习算法的前提假设是无标签的数据和有标签的数据不一定满足一样的分布，而无监督学习算法的前提假设是两者的分布是一样的。我们先来介绍一下特征学习：我们之前讲过自编码器，输入时有标签的数据集对于

2015-03-20 14:55:58 1187

原创 Remove Duplicates from Sorted List

Remove Duplicates from Sorted ListGiven a sorted linked list, delete all duplicates such that each element appear only once.For example,Given 1->1->2, return 1->2.Given 1->1->2->3->3, re

2015-03-03 21:16:20 345

原创 Partition List

Partition List TGiven a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.You should preserve the original relative order of th

2015-03-03 21:13:46 361

原创深度学习基础（五）Softmax Regression

function [softmaxModel] = softmaxTrain(inputSize, numClasses, lambda, inputData, labels, options)%softmaxTrain Train a softmax model with the given parameters on the given% data. Returns softmaxOptT

2015-02-28 10:28:07 831

原创 Add Two Numbers

Add Two Numbers You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers

2015-02-17 11:09:58 478

原创 Gas Station

Gas Station There are N gas stations along a circular route, where the amount of gas at station i is gas[i].You have a car with an unlimited gas tank and it costs cost[i] of gas to travel

2015-02-15 11:06:26 531

原创 Valid Sudoku

Valid SudokuDetermine if a Sudoku is valid, according to: Sudoku Puzzles - The Rules.The Sudoku board could be partially filled, where empty cells are filled with the character '.'

2015-02-04 22:05:56 458

原创 3Sum

3SumGiven an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note:Elements

2015-02-04 10:51:03 421

原创 Two Sum

Two SumGiven an array of integers, find two numbers such that they add up to a specific target number.The function twoSum should return indices of the two numbers such that they add up to th

2015-02-04 10:05:25 418

原创 Longest Consecutive Sequence

Longest Consecutive Sequence Given an unsorted array of integers, find the length of the longest consecutive elements sequence.For example,Given [100, 4, 200, 1, 3, 2],The longest cons

2015-02-04 09:54:44 419

原创 Median of Two Sorted Arrays

Median of Two Sorted Arrays There are two sorted arrays A and B of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).

2015-02-04 09:05:52 410

Active shape model

viola_jones face detect

基于AdaBoost 算法的人脸检测

DictionaryLearning

空空如也