Decomposition (Divide and Conquer)

definition breaking down the complex problem into smaller manageable parts.
*Note: every subsolution needs to be synthesized to form the final solution *

Recursion

definition the function calls itself
function body: base case(conquer), recursive step(divide)
*But recursion may not be efficient

Recursion: base case+recursive rules

• sometimes

Binary trees expression: e.g. [[left child], node, []]

answerList = random.sample([1,2,3,4,5,6,7,8,9,0], 4) choose 4 unique elements from the sample list [read more]
Integer is not iteratable
Three steps

1. initialization: draw the maze, set the boundaries, set the target
2. get the input: move the marble, and get the new positions
3. check the boundaries

sum(board,[]) reduce the dimension of the list board

Fundamental knowledge

1. the index of tuple also starts from 0
2. interger is not iterable or subscriptable. i.e. 3[0] is TypeError
3. mutable objects pass themselves when there is function-call, that is parameter and argument point to the same list; immutable means pointing to a new object.

  para = para[:]```
But the case above, para is new copy of the original list 
# Discussion 
```python
while data['score'] != -1:
...

Main Programme should only show the top-level flow

Decomposition means focus.

Data base implementation

keyerror is common

Module

any python files can be references as a module
module name is the filename without '.py'

when we import the module, the main program will be executed.

Unit Test

in modules, the main program is necessary for the unit test within the module

1. before imported, the codes in the main program should be commented to "hide" the program
2. A better way, add a line before the main program

if __name__='__main__':

• when the module file is executed as