QA Official

Several Algorithms for Selective Sorting

https://qaofficial.com/post/2019/05/21/69749-several-algorithms-for-selective-sorting.html 2019-05-21
The basic idea of selective sorting is to select the record with the smallest keyword from N-I+1 (I = 1,2, ..., N-1) records as the I-th element in the ordered sequence.Ranking of The Locksmith void SelectSort(Elem R[],int n){ //对R[1]~R[n]做简单选择排序 int i; for(i=1;i<n;i++){ j=SelectMinKey(R,i); //在R[i...

Training of word2vec model under Spark

https://qaofficial.com/post/2019/05/21/68852-training-of-word2vec-model-under-spark.html 2019-05-21
1. Introduction The previous section introduced synonyms for Word2Vec model training, so under the condition of large amount of data, we naturally thought of spark for training.Here's how we implement model training on spark. 2, word segmentation The input of model training is the corpus of words, then word segmentation on spark must be realized. def split(jieba_list, iterator): sentences = [] for i in iterator: try: seg_list = [] #out_str = "

Turn: Let opencv output the score of face detection (confidence rate)

https://qaofficial.com/post/2019/05/21/70937-turn-let-opencv-output-the-score-of-face-detection-confidence-rate.html 2019-05-21
Let opencv output the score of face detection (confidence rate)

fingerprint module 1

https://qaofficial.com/post/2019/05/21/68890-fingerprint-module-1.html 2019-05-21
8.1 Does Mobile Phone Support Fingerprint frameworks Layer Configuration 1. Add to the compiled file under device PRODUCT_COPY_FILES += \ frameworks/native/data/etc/android.hardware.fingerprint.xml:$(TARGET_COPY_OUT_VENDOR)/etc/permissions/android.hardware.fingerprint.xml This will copy the configuration file to the phone. PackageMS will parse the file for this feature public static final String FEATURE_FINGERPRINT = "android.hardware.fingerprint"; system_Server decides whether to start FMS based on this feature. if (mPackageManager.hasSystemFeature(PackageManager.FEATURE_FINGERPRINT)) { traceBeginAndSlog("StartFingerprintSensor"); mSystemServiceManager.startService(FingerprintService.class); traceEnd(); }

randomforest &amp;amp; gbdt &amp;amp; xgbost &amp;amp; lightgbm interview questions

https://qaofficial.com/post/2019/05/21/70865-randomforest-ampamp-gbdt-ampamp-xgbost-ampamp-lightgbm-interview-questions.html 2019-05-21
1. Knowledge Points 2. Feature Importance Assessment The tree-based integration algorithm has a very good feature, that is, the relative importance of the features used by the model can be output after the training of the model, which is convenient to understand which factors have a key impact on the prediction and effectively screen the features. Random Forest Error Rate Evaluation of Out-of-Bag DataSince RF is bootstrapping with resampling, the probability that a sample will not be sampled is\ lim _ {m \ rightarrow \ infty} (1-\ frac {1} {m}) m = \ frac {1} {e} \ thickrox 0.

summary of similarities and differences between rf and GBDT and Xgboost, plus lightgbm

https://qaofficial.com/post/2019/05/21/70861-summary-of-similarities-and-differences-between-rf-and-gbdt-and-xgboost-plus-lightgbm.html 2019-05-21
the same point (take care of the title): all use Bootstrap thought, Bootstrap is a kind of sampling method thought with put back Difference: Base Class Generator: RF uses regression tree or classification tree, GBDT and xgboost uses CART (regression tree) Split Node: RF: entropy or information gain or GiNi index is selected according to the selected tree type; GBDT: minimum mean square deviation is used in regression, and minimum GiNi index is used in classification;

C and C++ Differences and Connections (Extended Knowledge)

https://qaofficial.com/post/2019/05/20/72103-c-and-c-differences-and-connections-extended-knowledge.html 2019-05-20
2017/3/17 Review and Arrangement: C/C++ Differences and Connections; The difference between C and C++ is the question that is often asked in the interview. In line with the mentality of the upcoming interview, we will organize the knowledge and expand the small knowledge points. C/C++ Connection: C++ is a superset of C and is compatible with most C syntax structures.After all, cplusplus! C/C++ differences: The first thing you should think

C++ and Java

https://qaofficial.com/post/2019/05/20/72109-c-and-java.html 2019-05-20
Java and C++ are currently popular Object Oriented Programming. They all have three object-oriented features-inheritance, encapsulation and polymorphism.Generally speaking, C++ is compatible with C and adds object-oriented on the basis of C language, so C++ has both process-oriented and object-oriented characteristics.Java is a completely object-oriented language. It draws on many successful experiences of C/C++, but it also abandons many difficulties and "shortcomings" of C++, so it is easier to learn.

NumPy Concise Tutorial (II, Array 2)

https://qaofficial.com/post/2019/05/20/72164-numpy-concise-tutorial-ii-array-2.html 2019-05-20
NumPy array (2, operation of array) basic operation array arithmetic operations are performed element by element.After the array operation, a new array containing the operation results will be created. >>> a= np.array([20,30,40,50]) >>> b= np.arange( 4) >>> b array([0, 1, 2, 3]) >>> c= a-b >>> c array([20, 29, 38, 47]) >>> b**2 array([0, 1, 4, 9]) >>> 10*np.sin(a) array([ 9.12945251,-9.88031624, 7.4511316, -2.62374854]) >>> a<35 array([True, True, False, False], dtype=bool)Unlike

c++ encountered &amp;quot;this application has requested the runtime ... in anunusualway&amp;quot; while running the program.

https://qaofficial.com/post/2019/05/20/72116-c-encountered-ampquotthis-application-has-requested-the-runtime-...-in-anunusualwayampquot-while-running-the-program..html 2019-05-20
【Problem】 When I used c free to write C++, ios::noCreate was no longer used when I first discovered to operate on files, and the second was when I executed the following programIt is now suggested that this application has requested the runtime to terminate it. code is as follows: //随机访问二进制数据文件