201,200-degree data mining research and development engineer Pen test

A simple question
STL Vector Correlation in 1.c++
(1). What is the memory allocation of the Push_back function?
(2). The memory allocation of the clear function is implemented.


2. (This topic gives a C language code, let's find out the error in Foo function or unreasonable place) [the specific code is not clear except, probably as follows]


void foo (char a[100], cnt[256])
{
memset (CNT, 0, sizeof (CNT));

while (*a!= ' ")
{
++CNT[*A];
++a;
}
for (Char c= ' a '; c<= ' z '; ++c)
{
printf ("%c, D", C, Cnt[c]);
}
}


int main ()
{
Char a[100] = "Baidu abc";
Char cnt[256];

Foo (char a[100], cnt[256]);
}


Two. Algorithm design


1. The known function, rand (S,T), can give a decimal number of [s,t], using the function to give n random points in a garden with a radius of R, and to analyze the time complexity.


2. Known server can only store m request query, please give a design, from the user's request randomly out of M, and try to ensure that each query out of the same probability, less than the last time no one knows how much the user request.




Three.
Classification Clustering algorithm correlation (k-nn,linear SVM etc)
1. Give the following sample (box) in 1-adjacent, 3-adjacent, 5-adjacent label.
+

-+-
Square position
— —


2. The effect of the value of K on the algorithm (complexity, training accuracy, test accuracy, etc.)


3. A manufacturer prepares on-line an on-line picture classification algorithm, the data quantity is big, the server resources are limited, the inquiry time needs to be quicker, please in linear SVM, the logistic regression,discriminate regression and so on algorithm chooses one realization, And explain the reasons and analysis, and k-nn with the advantages and disadvantages of comparison.