# Tips for coding interview

This section will give a brief introduction of steps to get hired in a it-technology company:

1. Resume 
2. Data structure & Algorithm preparation
3. Submit an application
4. Mock interview
5. VISA application
6. Procedure of interview

The content of this section is summarised from a class in [BigO-coding](http://bigocoding.com/). You can have more insights on this topic and also valuable advises there.

## Resume

A perfect guideline for an attractive RESUME can be found [here.](https://www.careercup.com/resume/)

## Data structure & Algorithm preparation

There are several good recommendations to tackle this task:

* [interviewbit](https://www.interviewbit.com/practice/) -> practice atleast 200 problems here
* [leetcode](https://leetcode.com/problemset) -> practice atleast 300 problems here

Remember to count the time elapsed until you finish the problem. During a real interview, you should finish a task within a limited time.

## Submit an application

There are several ways to do this:

* directly apply in the website of a company interested -> successful rate of 0.01% due to so many perfect-CV from India or China, they have a team to buildup that kind of CV.
* join competitive programming contests of such company, this method is quite good because the top-100 is actually soldier of fortune so the company normally will perform an interview for top-1000 or top-10000 -> successful rate of 50%.
  * [google](https://codingcompetitions.withgoogle.com/codejam);
  * [facebook](https://www.facebook.com/hackercup/contest);
  * [codechef](https://www.codechef.com/) summarises all kinds of contests.
* referral from someone ([Big-O center](http://bigocoding.com/) reserves 10 slots for its member every year from September to November).
  * English: TOEFL 100 iBT, IELTS 7.5.
  * Online survey & test: one-tme submission only. 

## Mock interview

Several of the best site to practice a mock interview.

* [pramp](https://www.pramp.com/)
* [interviewing](https://interviewing.io/) 

Tips:

* choose a good time slot to have an interview with Americans.
* do about 20 interviews 
* provide feedbacks as details as possible.

[Hal Burch](https://train.usaco.org) conducted an analysis over spring break of 2000 and made an amazing discovery: there are only 16 types of programming contest problems; furthermore, the top several comprise almost 80% of the problems. Here they are:

* Dynamic programming
* Greedy
* Complete search
* Flood fill
* Shortest path
* Recursive search techniques
* Minimum spanning tree
* Knapsack
* Computational geometry
* Network flow
* Eulerian path
* Two-Dimensional convex hull
* BigNums
* Heuristic search
* Approximate search
* Ad-Hoc problems

The most challenging problems are Combination Problems which involve a loop (combinations, subsets, etc.) around one of the above algorithms - or even a loop of one algorithm with another inside it. These seem extraordinarily tricky to get right, even though conceptually they are *obvious*. **Ad hoc** problems are those whose algorithms do not fall into standard categories with well-studied solutions. Each ad hoc problem is different; no specific or general techniques exist to solve them.

## VISA application

A good webiste with good details and tips for working visa application can be found [here.](https://www.myvisajobs.com/)

## Procedure of interview

There are many round of interview:

* Round 1: for both Internship and Full-time, phone interview about 45', 1 to 2 questions with a difficulty equals to A and B of Div. 2 contest (cf) -> data structures and algorithms.
* Round 2: for both Internship and Full-time, phone interview about 45', 1 to 2 questions with a difficulty equals to B and C or B+ (optimisation of B to reduce time- or space-complexity) of Div. 2.
* Round 3: 
  * Internship: maybe have or havent. Havent: totally failed or totally passed. Have -> another chance.
  * Full-time: definitely, phone interview about 60', 1 to 2 questions with a difficulty equals to B and C of Div. 2.
* Round 4: full-time only, onsite, from morning to evening. If there is an invitation for lunch -> definitely failed. C of Div. 2.
* Round 5, 6: D of Div. 2. Projects finished. Preference teams to work in ?
* Apple only: round 7 to 12 interview with different people, different team. 
* Matching team: passed, enquiry from different teams. This round may last in 3 months. Without 3 months, if there is no team for matching -> failed.

## Level:

Compare to the level of programmers in codeforces, the correlations between the capability required to work in different countries/regions are:

![Coding level in Codeforces](https://512166478-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LqHjinTfO5Q8jG0YS63%2F-LrDPmPahw46qSjRCD6A%2F-LrDPnMqeMDA7IC9Q5zU%2Flevel.png?generation=1571126197246378\&alt=media)

| Class            | Color       | Point     |
| ---------------- | ----------- | --------- |
| Blue             | cyan        | 1400-1600 |
| Singapore        | purple      | 1900-2100 |
| European/America | yellow      | 2100-2300 |
| TopDEV           | strong pink | 2400-2600 |

## Where to head for

* [**Two-sigma**](https://www.twosigma.com/)
* [**World Quant** Vietnam](https://www.weareworldquant.com/en/careers/)
* [**Anduin Transactions** Vietnam](https://www.anduintransact.com/)
* quantitative jobs search in Vietnam