American group reviews 2017 autumn recruit written test true problem-algorithmic engineer a part of the detailed _ American group pen test

31 Balanced binary tree with a height of 4 with a minimum number of nodes ()

A. 5

B. 6

C. 7

D. 8

Idea: Assuming that a balanced binary tree with a height of n has at least f (n) nodes, then f (n) satisfies: f (n) = f (n-1) + f (n-2) + 1 (n >=2).

The boundary condition is: F (0) = 0,f (1) = 1,

41 A total of three nodes of the two-fork tree may appear how many kinds of structure

A. 3

B. 4

C. 5

D. 6

Idea: Assuming there are n nodes, 1,2,3 N, the number of two-forked trees with different structures is H (n), assuming h (0) = 1, if node 1 is the root node, the left subtree is empty, and the right subtree is an H (n-1) problem, the two sides are independent, so multiply, h (0) *h (n-1), Node 2 as is the root node, the left subtree is a node, the right subtree n-2 nodes, h (1) *h (n-2), and so on, and finally,

H (N) = h (0) *h (n-1) + H (1) *h (n-2) + H (2) *h (n-3) + ... + h (n-1) *h (0) is the size of n Cattleya.

Additional forms of the Cattleya number:

H (N) = C (2n,n)/(n+1)

H (n) = C (2n,n)-C (2n,n-1)

14 Which of the following are discriminant models

Maximum entropy

Decision Tree

Conditions with the airport

Naive Bayes

Ideas:

discriminant analysis of generation model naïve Bayesian K-nearest neighbor (KNN) mixed Gaussian model hidden Markov model (HMM) Bayesian network sigmoid belief Networks Markov random field (Markov Random Fields) Depth Belief network (DBN)

discriminant Model linear regression (Linear regression) logistic regression (logistic regression) neural Network (NN) support vector machine (SVM) Gaussian process (Gaussian process) condition with an airport (CRF) CART ( Classification and regression tree)