problem-solving-approach.md

Problem solving

Some tip for solving problems:

• Devise a plan for solving problems
• Master common problem solving patterns

Steps in solving problems

1. Understand problem

Questions to ask yourself:

* Can I restate the problem in my own words?

* What are the input that go into the problem?

* What are the otputs that should come from the solution to the problem?

* Can outputs be determined from inputs. Do I have enough informations to solve the problem

* How should I label the important pieces of data that are a part of problem?

2. Concrete examples

Go throw examples like unit testing

* Start with simple examples
* Progress to more complex examples
* Explore examples with empty inputs
* Explore examples with invalid input

3. Break it down

Explicitly write out the steps you need to take like comments

```
// validate input
// get user from database
// check if user exists
// update user in database
// send mail
// return response
```

4. Solve or simplify

Solve the problem if you cant, solve a simpler problem, dont stuck, gain some experience

* Find the core difficulty in what you are trying to do
* Temporarily ignore that difficulty 
* Write a simplified solution
* Then incorporate that difficulty back in

5. Loop back and refactor

Refactoring questions

* Can I check the result?
* Can you derive the result differently?
* Can you understand it at a glance?
* Can you use the result or method for some other problem?
* Can you improve the performance of your code solution?
* Can you think of other ways to refactor (code styles, etc.)?
* How have other people solved this problem?

Example: Instead of regexp check you can user check based on characters code

Code between:

* 47 and 58 are numeric
* 64 and 91 are upper alpha
* 96 and 123 lower alpha