07 2020 档案
摘要：机器学习算法-VAE 1. VAE模型推导 1.1 算法引入 在EM算法中，隐变量的最优分布$q^{\star}(\mathbf)$是在观测数据给定时的条件分布$p(\mathbf|\mathbf)$，此时对应的证据下界与似然函数相等。但是在实际中，后验概率可能很难计算甚至不能计算，这时EM算法
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摘要：机器学习算法-GMM和EM算法 1. GMM模型 聚类问题是一个经典的无监督任务，其目标是将 \(N\) 个 \(D\) 维数据 \(\{\bf{x}_i\}_{i=1}^N\) 分成$K$个簇，使得每个簇中的样本尽可能相似。GMM算法对数据分布做了一些假设： 第$k$个簇数据点服从正态分布，即
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摘要：Range Sum Query - Mutable Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive. The update(i, val) fun
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摘要：Additive Number Additive number is a string whose digits can form additive sequence. A valid additive sequence should contain at least three numbers.
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摘要：Range Sum Query 2D - Immutable Given a 2D matrix matrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1, col
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摘要：Longest Increasing Subsequence Given an unsorted array of integers, find the length of longest increasing subsequence. Example: Input: [10,9,2,5,3,7,1
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摘要：Game of Life According to the Wikipedia's article: "The Game of Life, also known simply as Life, is a cellular automaton devised by the British mathem
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摘要：Ugly Number II Write a program to find the n-th ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. Example: Inpu
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摘要：H-Index II Given an array of citations sorted in ascending order (each citation is a non-negative integer) of a researcher, write a function to comput
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摘要：Single Number III Given an array of numbers nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find
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摘要：Search a 2D Matrix II Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties: Integers in
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摘要：Sliding Window Maximum Given an array nums, there is a sliding window of size k which is moving from the very left of the array to the very right. You
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摘要：Product of Array Except Self Given an array nums of n integers where n > 1, return an array output such that output[i] is equal to the product of all
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摘要：在VSCode中写python时，import numpy和matplotlib总是报错找不到模块，用conda list和pip list看到都安装了numpy，前后折腾了很久遇到了好几个问题： 无法从PIL中导入Image 无法导入numpy.multiarray 无法找到numpy 前后尝试的
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摘要：Lowest Common Ancestor of a Binary Tree Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the de
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摘要：Kth Smallest Element in a BST Given a binary search tree, write a function kthSmallest to find the kth smallest element in it. Example 1: Input: root
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摘要：Majority Element II Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times. Note: The algorithm should run in linear
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摘要：Summary Ranges Given a sorted integer array without duplicates, return the summary of its ranges. Example 1: Input: [0,1,2,4,5,7] Output: ["0->2","4->
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摘要：Basic Calculator Implement a basic calculator to evaluate a simple expression string. The expression string may contain open ( and closing parentheses
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摘要：Rectangle Area Find the total area covered by two rectilinear rectangles in a 2D plane. Each rectangle is defined by its bottom left corner and top ri
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摘要：Count Complete Tree Nodes Given a complete binary tree, count the number of nodes. Note: Definition of a complete binary tree from Wikipedia: In a com
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摘要：Maximal Square Given a 2D binary matrix filled with 0's and 1's, find the largest square containing only 1's and return its area. Example: Input: 1 0
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摘要：Combination Sum III Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each co
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摘要：Kth Largest Element in an Array Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not th
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摘要：House Robber II You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed. All houses at t
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摘要：LeetCode中出现了2sum, 3sum, 4sum的问题，文章给出了一种通用的解法，想法是将n_sum问题转换为(n-1)_sum问题，具体步骤如下： 定义函数sum(n, target)，表示求解和为target的nsum问题 step1：排序，这样2sum问题可以用双指针解决，时间复杂度为
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摘要：机器学习算法——SVM 1. 背景 在线性分类任务中，对于同一个数据集，可能有多个分离超平面。例如在下图中，H2和H3都能够将白色点和黑色点分离开来，那么在这些分界面中，是否存在一个最优的分界面？一个直观的想法是，离所有点都比较远的分割面会是一个好的分割面。可以证明，这样的最优分割面是唯一的。因
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摘要：Add and Search Word - Data structure design Design a data structure that supports the following two operations: void addWord(word) bool search(word) s
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摘要：Course Schedule II There are a total of n courses you have to take, labeled from 0 to n-1. Some courses may have prerequisites, for example to take co
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摘要：Minimum Size Subarray Sum Given an array of n positive integers and a positive integer s, find the minimal length of a contiguous subarray of which th
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摘要：Implement Trie (Prefix Tree) Implement a trie with insert, search, and startsWith methods. Example: Trie trie = new Trie(); trie.insert("apple"); trie
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摘要：Count Primes Count the number of prime numbers less than a non-negative number, *n*. Example: Input: 10 Output: 4 Explanation: There are 4 prime numbe
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摘要：Isomorphic Strings Given two strings *s* and *t*, determine if they are isomorphic. Two strings are isomorphic if the characters in *s* can be replace
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摘要：Course Schedule There are a total of numCourses courses you have to take, labeled from 0 to numCourses-1. Some courses may have prerequisites, for exa
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摘要：Remove Linked List Elements Remove all elements from a linked list of integers that have value *val*. Example: Input: 1->2->6->3->4->5->6, val = 6 Out
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摘要：机器学习之树模型 大纲 决策树和回归树模型：ID3， C4.5，CART AdaBoost框架 提升树：梯度提升树 决策树 决策树模型可以看做是if-else指令集合，通过对特征空间的划分来完成分类或者回归任务。以下图中的分类任务为例，假设数据集包含了： 三个类别：黄色、蓝色、绿色 两个维度的特征空
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摘要：Happy Number Write an algorithm to determine if a number n is "happy". A happy number is a number defined by the following process: Starting with any
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摘要：Bitwise AND of Numbers Range Given a range [m, n] where 0 ⇐ m ⇐ n ⇐ 2147483647, return the bitwise AND of all numbers in this range, inclusive. Exampl
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摘要：Number of Islands Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by
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摘要：Binary Tree Right Side View Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered
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摘要：House Robber You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constrain
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摘要：Number of 1 Bits Write a function that takes an unsigned integer and return the number of '1' bits it has (also known as the Hamming weight). Example
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摘要：在阅读论文Understanding Black-box Predictions via Influence Functions时，看见了一种计算逆矩阵$H^{-1}$的方法： 定义$H_j^{-1} = \sum_j (I-H)i$，有$\mathbb[H_j{-1}] = H{-1}(j\rig
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摘要：Reverse Bits Reverse bits of a given 32 bits unsigned integer. Example 1: Input: 00000010100101000001111010011100 Output: 0011100101111000001010010100
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摘要：Best Time to Buy and Sell Stock IV Say you have an array for which the i-th element is the price of a given stock on day i. Design an algorithm to fin
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摘要：Best Time to Buy and Sell Stock III Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to fin
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摘要：Best Time to Buy and Sell Stock II Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find
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摘要：Best Time to Buy and Sell Stock Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to
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摘要：Largest Number Given a list of non negative integers, arrange them such that they form the largest number. Example 1: Input: [10,2] Output: "210" Exam
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摘要：Fraction to Recurring Decimal Given two integers representing the numerator and denominator of a fraction, return the fraction in string format. If th
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摘要：Compare Version Numbers Compare two version numbers version1 and version2. If *version1* > *version2* return 1; if *version1* < *version2* return -1;o
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摘要：机器学习算法——kNN 1. 算法原理 基本思想是物以类聚，相同类别的样本之间在特征空间中应当聚集在一起，因此对于新的数据点，根据其附近的K个邻居的类型可以对其进行预测。如下图所示，假设红、绿、蓝三种颜色的点分布在二维空间中，这对应着分类任务中的训练样点包含了3个类别，特征数量为2。如果现在我们希望
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摘要：Maximum Gap Given an unsorted array, find the maximum difference between the successive elements in its sorted form. Return 0 if the array contains le
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摘要：Find Peak Element A peak element is an element that is greater than its neighbors. Given an input array nums, where nums[i] ≠ nums[i+1], find a peak e
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摘要：Find Minimum in Rotated Sorted Array II Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e., [0,1,2,4
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摘要：Find Minimum in Rotated Sorted Array Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e., [0,1,2,4,5,
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摘要：Maximum Product Subarray Given an integer array nums, find the contiguous subarray within an array (containing at least one number) which has the larg
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摘要：Reverse Words in a String Given an input string, reverse the string word by word. Example 1: Input: "the sky is blue" Output: "blue is sky the" Exampl
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摘要：Sort List Sort a linked list in O(n log n) time using constant space complexity. Example 1: Input: 4->2->1->3 Output: 1->2->3->4 Example 2: Input: -1-
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摘要：Evaluate Reverse Polish Notation Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, /. Each opera
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摘要：Insertion Sort List Sort a linked list using insertion sort. A graphical example of insertion sort. The partial sorted list (black) initially contains
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摘要：发现了一个好玩的模板Silence，地址为[https://www.cnblogs.com/esofar/p/cnblogs-theme-silence.html] 按照github上的配置教程即可完成配置~
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