## 3d machine learning open3d learning record -- point cloud 2

preface
Follow the previous section Point cloud 1 Data address of this section: link: https://pan.baidu.com/s/1O4s8tFOvExhuKMl2OCv4Kg Extraction code: 82u1
1. Point cloud clipping
Code first
import open3d as o3d
pcd=o3d.io.read_point_cloud("./test_data/Crop/fragment.ply")
val=o3d.visualization.read_selection_polygon_volume("./test_data ...

Added by **project168** on *Thu, 20 Jan 2022 00:29:55 +0200*

## [sitch cup · blue bridge on cloud - algorithm training camp] week 2

1. With score
Problem description
100 can be expressed as a fractional form: 100 = 3 + 69258 / 714.
It can also be expressed as: 100 = 82 + 3546 / 197.
Note: in the band fraction, the numbers 1 ~ 9 appear respectively and only once (excluding 0).
Like this band fraction, 100 has 11 representations.
Input format
Read a positive intege ...

Added by **Litninfingers63** on *Wed, 19 Jan 2022 23:28:25 +0200*

## leetcode15. Sum of three (medium)

Give you an array num containing n integers. Judge whether there are three elements a, b and c in num, so that a + b + c = 0? Please find all triples with sum 0 and no repetition.
Note: the answer cannot contain duplicate triples.
Example 1: Input: num = [- 1,0,1,2, - 1, - 4] Output: [- 1, - 1,2], [- 1,0,1]]
Example 2: Input: num = [] Output ...

Added by **XtacY** on *Wed, 19 Jan 2022 21:55:24 +0200*

## Solutions to the 9th Blue Bridge Cup Undergraduate Java group B [provincial competition]

1. What day
Title Description
This question is a blank filling question. You only need to calculate the result and use the output statement in the code to output the filled result.
January 1, 2000 is the 11th day of that year.
So, May 4, 2000, is the first day of that year?
Operating limits
Maximum running time: 1sMaximum operating me ...

Added by **olaf** on *Wed, 19 Jan 2022 21:31:16 +0200*

## [daily question] DP algorithm - change and question + vowel sequence statistics

⭐ New pit in winter vacation -- daily question notes of code Fox
1220. Count the number of vowel sequences - Hard
Title Description:
Give you an integer n, please help us count how many strings with length n can be formed according to the following rules:
Each character in the string should be a lowercase vowel ('a ',' e ',' I ',' o ',' U ...

Added by **o2cathy** on *Wed, 19 Jan 2022 21:11:52 +0200*

## Machine learning Note 6: integrated learning at the bottom of Python

preface
In the supervised learning algorithm of machine learning, our goal is to learn a stable model with good performance in all aspects, but the actual situation is often not so ideal. Sometimes we can only get multiple preferred models (weak supervised model, which performs better in some aspects). Three cobblers make Zhuge Liang. Ensemble ...

Added by **simmsy** on *Wed, 19 Jan 2022 19:45:47 +0200*

## LeetCode-139 - word splitting

Word splitting
Title Description: given a non empty string s and a list wordDict containing non empty words, determine whether s can be divided into one or more words in the dictionary by spaces.
explain:
Words in the dictionary can be reused when splitting.
You can assume that there are no duplicate words in the dictionary.
See LeetCode's o ...

Added by **DF7** on *Wed, 19 Jan 2022 18:21:58 +0200*

## JAVA: two point exercise -- previous test question interval displacement

1, Problem description
There are n closed intervals D1,..., Dn on the number axis. The interval Di is described by a pair of integers [ai, bi], which satisfies AI < Bi. It is known that the sum of the lengths of these intervals is at least 10000. Therefore, by appropriately moving these intervals, you can always make their "union& ...

Added by **Chips** on *Wed, 19 Jan 2022 16:40:21 +0200*

## Java -- Interpretation of HashMap source code (Java jdk1.7)

Core parameters
/**
* The table, resized as necessary. Length MUST Always be a power of two.
*/
transient Entry<K,V>[] table = (Entry<K,V>[]) EMPTY_TABLE;
/**
* The number of key-value mappings contained in this map.
*/
transient int size;
/**
* The next size value at which to resize ...

Added by **jackthebookie** on *Wed, 19 Jan 2022 16:24:08 +0200*

## Data structure and algorithm: the basic part of tree structure

Basic part of tree structure
1, Binary tree
1. Why do you need a tree data structure
1.1 analysis of array storage mode
Advantages: it is fast to access elements by subscript. For ordered arrays, binary search can also be used to improve the retrieval speed. Disadvantages: if a specific value is to be retrieved, or the inserted value (in a ...

Added by **ealderton** on *Wed, 19 Jan 2022 14:01:14 +0200*