Grokking some algorithms via recursion and got a question

Question

My task is to define a function, that will find maximum in the list via recursion. Can't made it by myself, looked in the "Answer" chapter, rewrite it and still can't understand

def max(list):
if len(list) == 2: #basic case, if list consists of 2 elements
return list[0] if list[0] > list[1] else list[1]
print (list[0], list [1], list[2]) #print to see what elements are selected
sub_max = max(list[1:])
print (sub_max) #print to see what's in there at the moment
return list[0] if list[0] > sub_max else sub_max

print(max([1, 3, 17, 6, 23, 45, 2, 7, 11, 8, 29, 15, 20]))

When I ran the code, the first thing shown is lists of three elements (i.e. 1, 3, 17; 3, 17, 6; till the last 29, 15,20). And then list of sub_maxs, as if the code runs from the end. Why does it happens so? I can't see it in the code (for now)

Answer 1

I think sub_max = max(list[1:]) is minimizing list till the last 2 elements, and then returning back through 'call stack'. Am I right? Or I still don't get it?

Answer 2

def max(val,lst):
if(len(lst)==1):
if(val>lst[0]):
return val
else:
return lst[0]
if(val<lst[0]):
val=lst[0]
return(max(val,lst[1:]))

lst=[1, 3, 17, 6, 23, 45, 2, 7, 11, 8, 29, 15, 20]
print(max(lst[0],lst[1:]))

Answer 3

Check this one