algorithm - What does stack[-1] mean in a pseudocode? -

def _all_simple_paths_graph(g, source, target, cutoff=none): if cutoff < 1:     return visited = [source] stack = [iter(g[source])] while stack:     children = stack[-1]     child = next(children, none)     if child none:         stack.pop()         visited.pop()     elif len(visited) < cutoff:         if child == target:             yield visited + [target]         elif child not in visited:             visited.append(child)             stack.append(iter(g[child]))     else: #len(visited) == cutoff:         if child == target or target in children:             yield visited + [target]         stack.pop()         visited.pop() 

i find code on link.

but did not understand statements, following

• children = stack[-1] // stack[-1] mean?

• child = next(children, none) // child list or children list?

• stack = [iter(g[source])] // iter?

• if child none: // guess if child empty (child list).

• visited = [source] // that?

• yield visited + [target] // yield?

can explain me? trying rewrite in c.

it looks python code

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1) stack[-1] means give last element.

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2) children variable, code holds last element of list stack

children = stack[-1] 

child whatever next() function returns, looks of it, looks variable.

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4) if child none: if next() function returns none