#@title $`$AND$\_$OR$\_$Scheduler$`$ implementation

class AND$\_$OR$\_$Scheduler$($object$)$:

def $\_\_$init$\_\_($self$)$:

# It is up to you to implement the initialization.

### YOUR SOLUTION HERE

def add$\_$and$\_$task$($self$,$ t$,$ dependencies$)$:

$"""$Adds an AND task t with given dependencies."""

### YOUR SOLUTION HERE

def add$\_$or$\_$task$($self$,$ t$,$ dependencies$)$:

$"""$Adds an OR task t with given dependencies."""

### YOUR SOLUTION HERE

@property

def done$($self$)$:

### YOUR SOLUTION HERE

@property

def available$\_$tasks$($self$)$:

$"""$Returns the set of tasks that can be done in parallel.

A task can be done if:

$-$ It is an AND task, and all its predecessors have been completed, or

$-$ It is an OR task, and at least one of its predecessors has been completed.

And of course, we don't return any task that has already been

completed."""

### YOUR SOLUTION HERE

def mark$\_$completed$($self$,$ t$)$:

$"""$Marks the task t as completed, and returns the additional

set of tasks that can be done $($and that could not be

previously done$)$ once t is completed."""

### YOUR SOLUTION HERE

def show$($self$)$:

$"""$You can use the nx graph to display the graph. You may want to ensure

that you display AND and OR nodes differently."""

### YOUR SOLUTION HERE

# Tests $10$ points: Simple tests for AND nodes.

s $=$ AND$\_$OR$\_$Scheduler$()$

s$.$add$\_$and$\_$task$(\text{'}$a$\text{'},[\text{'}$b$\text{'},\text{'}$c$\text{'}])$

assert s$.$available$\_$tasks $==\{\text{'}$b$\text{'},\text{'}$c$\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$b$\text{'})$

assert r $==$ set$()$

assert s$.$available$\_$tasks $==\{\text{'}$c$\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$c$\text{'})$

assert r $==\{\text{'}$a$\text{'}\}$

assert s$.$available$\_$tasks $==\{\text{'}$a$\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$a$\text{'})$

assert r $==$ set$()$

assert s$.$available$\_$tasks $==$ set$()$

# Tests $10$ points: Simple tests for OR nodes.

s $=$ AND$\_$OR$\_$Scheduler$()$

s$.$add$\_$or$\_$task$(\text{'}$a$\text{'},[\text{'}$b$\text{'},\text{'}$c$\text{'}])$

assert s$.$available$\_$tasks $==\{\text{'}$b$\text{'},\text{'}$c$\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$b$\text{'})$

# Now $\text{'}$a$\text{'}$ becomes available.

assert r $==\{\text{'}$a$\text{'}\}$

# But note that $\text{'}$c$\text{'}$ is also available, even if useless.

assert s$.$available$\_$tasks $==\{\text{'}$a$\text{'},\text{'}$c$\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$a$\text{'})$

assert r $==$ set$()$

assert s$.$available$\_$tasks $==\{\text{'}$c$\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$c$\text{'})$

assert r $==$ set$()$

assert s$.$available$\_$tasks $==$ set$()$

# Tests $10$ points: Tests with both AND and OR nodes.

s $=$ AND$\_$OR$\_$Scheduler$()$

s$.$add$\_$and$\_$task$(\text{'}$a$\text{'},[\text{'}$b$\text{'},\text{'}$c$\text{'}])$

s$.$add$\_$or$\_$task$(\text{'}$b$\text{'},[\text{'}$b$1\text{'},\text{'}$b$2\text{'}])$

s$.$add$\_$or$\_$task$(\text{'}$c$\text{'},[\text{'}$c$1\text{'},\text{'}$c$2\text{'}])$

r $=$ s$.$mark$\_$completed$(\text{'}$b$1\text{'})$

assert s$.$available$\_$tasks $==\{\text{'}$b$\text{'},\text{'}$b$2\text{'},\text{'}$c$1\text{'},\text{'}$c$2\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$b$\text{'})$

assert $\text{'}$a$\text{'}$ not in s$.$available$\_$tasks

r $=$ s$.$mark$\_$completed$(\text{'}$c$1\text{'})$

assert $\text{'}$a$\text{'}$ not in s$.$available$\_$tasks

r $=$ s$.$mark$\_$completed$(\text{'}$c$\text{'})$

assert $\text{'}$a$\text{'}$ in s$.$available$\_$tasks

s $=$ AND$\_$OR$\_$Scheduler$()$

s$.$add$\_$or$\_$task$(\text{'}$a$\text{'},[\text{'}$b$\text{'},\text{'}$c$\text{'}])$

s$.$add$\_$and$\_$task$(\text{'}$b$\text{'},[\text{'}$b$1\text{'},\text{'}$b$2\text{'}])$

s$.$add$\_$and$\_$task$(\text{'}$c$\text{'},[\text{'}$c$1\text{'},\text{'}$c$2\text{'}])$

r $=$ s$.$mark$\_$completed$(\text{'}$b$1\text{'})$

assert s$.$available$\_$tasks $==\{\text{'}$b$2\text{'},\text{'}$c$1\text{'},\text{'}$c$2\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$c$1\text{'})$

assert s$.$available$\_$tasks $==\{\text{'}$b$2\text{'},\text{'}$c$2\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$c$2\text{'})$

assert s$.$available$\_$tasks $==\{\text{'}$b$2\text{'},\text{'}$c$\text{'}\}$

r $=$ s$.$mark$\_$completed$(\text{'}$c$\text{'})$

assert $\text{'}$a$\text{'}$ in s$.$available$\_$tasks

can someone help me with this code. What do I even input at the parts where it says ###YOUR SOLUTION HERE to get through all of the tests? This is driving me nuts.