programming languages ​​- Where can I find practical questions and solutions to such questions?

I am currently doing an ITEE exam and have reviewed a lot of previous exams. I agree in most areas because these reviews are very broad and include product management, software testing, memory architecture, and so on. But these particular issues using programming logic and mathematics are my weakest area.

I'm pretty much at the lower intermediate programming level, which means that OOP syntax and concepts such as encapsulation and abstraction, and so on. are suitable, but algorithmic tests are difficult.

  1. Where can I find and study these types of specific problems (especially in C)?
  2. If that is the problem of mathematics, what subjects should I study?
  3. Without labeling them simply as algorithms, what do these exam questions fall under?

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C ++ find the shortest path, reduce time complexity, dijkstra v Floyd Warshall Algorithm?

I have an algorithm that I am doing on a graph and I am trying to analyze how to speed it up. I would appreciate any comments.

The algorithm iterates on each edge of the graph.

For each edge, it (1) finds the shortest path from the input node of the graph to the edge source node. (Spot 1).

Then, it (2) finds the shortest path from the edge receiving node to the output node of the graph. (Task 2).

Doing this process for each edge is what makes it slow.

I'm currently using the dijkstra algorithm implemented with the use of priority queues in C ++ to find the shortest paths. According to this website, the complexity of this situation is O (ELogV)).

I think I can improve this in many ways.

  1. There are a lot of redundant calculations going on. Once I found the shortest way to a node at the exit, for example (Task 2)I know the shortest path for each node along the path from the node where I started. I'm wondering what is the effective way to implement this, which STL C ++ containers to use? Is it possible to estimate the decrease in complexity?

  2. A different approach would be to use the Floyd Warshall algorithm, which searches for the shortest distances between each pair of vertices in a DAG. The complexity of this is O (V ^ 3). Would it be faster to look for this information when calculating the shortest paths? How could I quantify how much this approach is faster.

google analytics – How can I find page views for the root of the website?

I just watched the tracking code on the site. The tracking code snippet is currently not configured for GA tracking. It is configured for Google Ads conversions, which also seems to be misconfigured via the gtag tracking code snippet.

This is your current tracking code snippet in which Google Ads ads were mistakenly entered as AW-AW-1071954721 instead of AW-1071954721:

    


To track multiple Google products with a single tracking code snippet, follow the steps in the following code example:


You will find more information about this in the development documents gtag.js
https://developers.google.com/gtagjs/devguide/add

postgresql – pg_restore: [archiver] did not find a magic string in the header of the file: please check the source URL and make sure it is accessible to the public

I've tried to transfer a dump file from my local Postgrel database (which I've loaded into Google Drive and accessible to the public) into my remote Heroku database with the help of Next URL:

heroku pg:backups:restore 'https://drive.google.com/open?id=dump_id_link_here' DATABASE_URL

I am already connected to my Heroku app from the terminal where I run the order.
but I had the same mistake twice. I was searching online and found topics such as pg_restore: (archiver) did not find a magic string in the file header, but I could not help but to do the link between the two, because I am very new to Postgrel. I hope you will indicate the problems. Much appreciated.

Starting restore of https://drive.google.com/open?id=dump_id_link_here to postgresql-symmetrical-52186... done

Stop a running restore with heroku pg:backups:cancel.

Restoring... !
▸    An error occurred and the backup did not finish.
▸    
▸    waiting for restore to complete
▸    pg_restore finished with errors
▸    waiting for download to complete
▸    download finished with errors
▸    please check the source URL and ensure it is publicly accessible
▸    Run heroku pg:backups:info r002 for more details.


=== Backup r002
Database:         BACKUP
Started at:       2019-09-14 21:14:26 +0000
Finished at:      2019-09-14 21:14:27 +0000
Status:           Failed
Type:             Manual
Backup Size:      0.00B (0% compression)

=== Backup Logs
2019-09-14 21:14:27 +0000 pg_restore: (archiver) did not find magic string in file header
2019-09-14 21:14:27 +0000 waiting for restore to complete
2019-09-14 21:14:27 +0000 pg_restore finished with errors
2019-09-14 21:14:27 +0000 waiting for download to complete
2019-09-14 21:14:27 +0000 download finished with errors
2019-09-14 21:14:27 +0000 please check the source URL and ensure it is publicly accessible

Ordinary Differential Equations – Find the speed at which two regions mingle.

I consider a problem in population biology, but I need help to perform a numerical calculation. I suspect that he will use ODEs.

Suppose the airplane is densely populated with particles of a density of $ delta_0 $ particles per unit area, except in a compact region $ Omega $in which there is no particle per unit area.

Let $ partial Omega $ indicate the limit of $ Omega $. Suppose that there is a small opening in the limit, that is to say. an appropriate subset $ ell subset partial Omega $. Suppose that the particles move according to the Brownian motion and that they can pass through the opening. $ ell $but not across the border $ partial Omega setminus ell $. See my diagram:

How the population density of $ Omega $ change over time? Of course as $ t to infty $ I know the mass of $ Omega $ approaches $ delta_0 $. I suspect that the rate of convergence towards $ delta_0 $ is determined by the length of $ ell $, and also by the variance of the random motion of the particles.

My question is: what expression of the demographic mass of $ Omega $ at one point $ t in Bbb R $?

homepage – How can I find page views for the root of the website in Google Analytics?

I just watched the tracking code on the site. The tracking code snippet is currently not configured for GA tracking. It is configured for Google Ads conversions, which also seems to be misconfigured via the gtag tracking code snippet.

This is your current tracking code snippet in which Google Ads ads were mistakenly entered as AW-AW-1071954721 instead of AW-1071954721:

    


To track multiple Google products with a single tracking code snippet, follow the steps in the following code example:


You will find more information about this in the development documents gtag.js
https://developers.google.com/gtagjs/devguide/add
anda .. once the GA tracking is set up and running, you will see the pages viewed in the Behavior> Site Content> All Pages report.

c ++ – Walk through a labyrinth and find the shortest path in C

Anyone can help me, I need to develop a recursive function that tests all the paths and returns the shortest.

Give a labyrinth in the form of a binary rectangular matrix (M, N), find the shortest path in the maze of an origin (xini, yini) to a given destination (xfim, yfim), where xini, yini, xfim, yfim are cells of the matrix MxN. The path must be built with cells having the value 1.

To find the shortest path in the labyrinth, you have to search all the possible paths in the maze, from beginning to end. The search starts from the origin in the informed cell of the matrix and explores the four possible directions, recursively checking whether they lead to the destination or not. The minimum path is updated if the target cell is found. If a path does not lead to the destination or if all routes have already been crawled from the current cell, take a step back. To make sure that the path is simple and contains no cycles, record the path of the cells involved in the array before exploring another cell. If the cell has already been visited, it is ignored (not browsed again).

Tip: To store the traversed paths, use an auxiliary matrix of the same size as the maze matrix to indicate whether the cell has already been visited (1) or not (0). If a path does not lead to the solution, the auxiliary matrix cell is deselected as visited.

My code up here:

#include 

//FUNÇÕES
int Labirinto(int m, int n, int mat()(n), int percorrido()(n), int xPos, int yPos, int xFin, int yFin, int *Atual)
{
    int menorCaminho;

    if(*Atual == 0)
    {
        menorCaminho = m*n;
    }

    *Atual = *Atual + 1;

    percorrido(xPos)(yPos) = 1;

In the code I wrote, the smallerPath variable does not get the contents of the current path, even though entering this if.

    if(xPos == xFin && yPos == yFin)
    {
        //Testa se um caminho mais curto foi encontrado
        if(menorCaminho > *Atual)
        {
            menorCaminho = *Atual;
        }

        *Atual = *Atual - 1;
        return menorCaminho;
    }

I also have problems here, as long as conditions are met, the first conditional is never executed.


    else if((mat(xPos+1)(yPos) == 1) && (xPos+1=0 && percorrido(xPos-1)(yPos) == 0)
    {
        Labirinto(m, n, mat, percorrido, xPos-1, yPos, xFin, yFin, &*Atual);
        percorrido(xPos-1)(yPos) = 0;
    }

    else if(mat(xPos)(yPos-1) == 1 && yPos-1>=0 && percorrido(xPos)(yPos-1) == 0)
    {
        Labirinto(m, n, mat, percorrido, xPos, yPos-1, xFin, yFin, &*Atual);
        percorrido(xPos)(yPos-1) = 0;
    }

    *Atual = *Atual - 1;
    return menorCaminho;
}

//INÍCIO DO FUNÇÃO PRINCIPAL
int main()
{
    int m, n, xInicial, yInicial, xFinal, yFinal, mat(100)(100), percorrido(100)(100), i, j, caminhoAtual = 0;

    scanf("%d" ,&m);
    scanf("%d" ,&n);
    scanf("%d" ,&xInicial);
    scanf("%d" ,&yInicial);
    scanf("%d" ,&xFinal);
    scanf("%d" ,&yFinal);

    for(i=0; i

algorithms – Find closed forms for return values


int coffee(int n) {
   int s = n * n;
   for (int q = 0; q < n; q++)
      s = s - q;
   for (int q = n; q > 0; q--)
      s = s - q;
   return s + 2;
}

int tea(int n) {
    int r = 0;
    for (int i = 1; i < n*n*n; i = i * 2)
        r++;
    return r * r;
}

int mocha(int n) {
    int r = 0;
    for (int i=0; i<=n; i = i+16)
        for (int j=0; j

I'm trying to find the value back in terms of $ n $ for coffee, tea, mochabut I'm stuck right now.

I know coffee will return 2 as the code follows:

$ s = n ^ 2 $

$ s = n ^ 2 - displaystyle sum_ {q = 0} ^ {n-1} q = n ^ 2 - dfrac {n (n-1)} {2} $

$ s = n ^ 2 - dfrac {n (n-1)} {2} - displaystyle sum_ {q = 1} ^ nq = n ^ 2 - dfrac {n (n-1)} {2} - dfrac {n (n + 1)} {2} = 0 $

Then, $ s = 0 + 2 $.

However, I can not understand tea, mocha, and espressobecause they do not follow the increments of +1. Could someone help me calculate the return value in terms of $ n $?

imac – How to find the speed and the parameters CL of the DDR3 SODIMM?

I bought a pair of SODIMM DDR3 1866 MHz Crucial of 8 GB for my iMac 27 5K Retina late 2015. I suspect that the SODIMM that I received measures 1600 MHz, maybe a counterfeit.

Here is my question

  1. Is there a way to read the SPD data for speed, CL parameters, and manufacturer ID?
  2. How can I find the actual speed. Does the system -> RAM report match the actual speed or SPD data?

  3. How can I check if it is a true Crucial memory?

The Crucial reference number is CT102464BF186D.C16FN.

CT102464BF186D

The marking on the Micron DRAM chip is D9QBJ.

D9QBJ

According to Micron, the reference number is MT41K512M8RH-125: E. Here is the link for the datasheet. -125 means a rating of 1.25nsec. 1 / 1.25 ns = 800 MHz, which corresponds to 1600 MHz since the DDR is a "double data rate".

How to find a better bearing supplier? – Advertising, offers

Looking for a bearing supplier? The best way to find a bearing supplier is to do your research in advance. This will help you find a reputable, competent and qualified supplier. There are also many ways to find a provider.

Getting recommendations is the first step to finding a potential supplier. You can request a list of recommendations from people who frequently need bearings. Distributors can be a very good source of recommendations, assuming they have already established good relationships with these professionals.

Similarly, people who have been working in the industry for a very long time can help you find a reliable supplier. Then it is always good that you can follow up with your prospects. This will allow you to find out more about their services, prices and license information.

It is also important to note that when you call a potential supplier, you need to know more about the lists of brands provided. You should also ask them if they can meet your requests and your bearing requirements. Some providers, for example, require full payment at the beginning of the service, while others offer more flexible payment terms.

It is also important to have their license number so you can check with the Department of Commerce or Commerce. It is very important to know if the company is legitimate and if it has a license to operate. After taking the time to find these suppliers, the information must be kept for future requests.

It's also a good idea if you can call them periodically so you can ask them if they still have business. This will help you determine if the products and services offered are always the same. You should also consider some tips when you prefer to wait for offers from various suppliers.

You must at least select suppliers who can give you a rough estimate of the bearing costs. This will help you decide if the prices are competitive or not. If you urgently need bearings, consult an expert dealer who will give you suggestions and recommendations, as he can give you many tips and useful information.

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