Tree Traversal Target: 10s
Push all left children, pop and process, go right. The fundamental iterative tree pattern.
def inorder(root):
res, stack = [], []
cur = root
while cur or stack:
while cur: # go left as far as possible
stack.append(cur)
cur = cur.left
cur = stack.pop() # process node
res.append(cur.val)
cur = cur.right # go right
return resType it from memory. Go.