The last part was difficult for me! Took me some time to figure out the small details to take care of.

For now here is my Python code. I am sure it can be simplified by a lot and made much more easy to read. Hopefully I will find time to do it later.

I am building a tree to solve this problem.

importcopywithopen('input')asf:data=f.readlines()classNode:def__init__(self,name,parents,children):self.name=nameself.parents=parentsself.parents_copy=parentsself.children=childrendef__repr__(self):parents=[p.nameforpinself.parents]ifself.parentselseNonechildren=[c.nameforcinself.children]ifself.childrenelseNonereturn'Node(name={}, parents={}, children={})'.format(self.name,parents,children)defadd_parent(self,parent):ifself.parents:self.parents.append(parent)else:self.parents=[parent]self.parents_copy=self.parents[:]defremove_parent(self,parent):ifself.parents_copy:self.parents_copy.remove(parent)defadd_child(self,child):ifself.children:self.children.append(child)else:self.children=[child]defis_root(self):returnself.parents_copy==[]nodes={}fordindata:node=nodes.get(d[5],Node(d[5],[],[]))child=nodes.get(d[36],Node(d[36],[],[]))node.add_child(child)child.add_parent(node)nodes[d[5]]=nodenodes[d[36]]=childnodes_bak=copy.deepcopy(nodes)# Part 1:
# Traverse the tree:
path=[]job_times={}whilelen(nodes):# Find roots:
roots=[nforninnodes.values()ifn.parents_copy==[]]first_root=min(roots,key=lambdan:n.name)# Execute first_node and remove it as parent from its children:
forcinfirst_root.children:c.remove_parent(first_root)# Remove node from global nodes list:
delnodes[first_root.name]path.append(first_root.name)print('Part 1:')print(''.join(path))# Part 2:
# Traverse the tree:
nodes=nodes_bakpath=[]worker_times={'0':0,'1':0,'2':0,'3':0,'4':0}job_times={}whilelen(nodes):# Find roots:
roots=[nforninnodes.values()ifn.parents_copy==[]]# Select first_root by earliest time to add:
min_time=float('inf')first_root=roots[0]forrinroots:# Time for all parents to have finished
iflen(r.parents)>=2:max_parent_time=max(job_times.get(p.name,0)forpinr.parents)eliflen(r.parents)==1:max_parent_time=job_times.get(r.parents[0].name,0)else:max_parent_time=0ifmax_parent_time<=min_time:ifmax_parent_time==min_time:first_root=min(first_root,r,key=lambdan:n.name)else:first_root=rmin_time=max_parent_time# Select the worker that finishes earliest:
earliest_worker=min(worker_times,key=worker_times.get)worker_times[earliest_worker]=(max(min_time,worker_times[earliest_worker])+ord(first_root.name)-4# Converts ASCII to decimal with time adjustment
)# Adding total time it took for job to finish:
job_times[first_root.name]=worker_times[earliest_worker]# Execute first_node and remove it as parent from its children:
forcinfirst_root.children:c.remove_parent(first_root)# Remove node from global nodes list:
delnodes[first_root.name]print('Part 2:')print(max(worker_times.values()))

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The last part was difficult for me! Took me some time to figure out the small details to take care of.

For now here is my Python code. I am sure it can be simplified by a lot and made much more easy to read. Hopefully I will find time to do it later.

I am building a tree to solve this problem.