Tree Implementation with Python
List of List
代码如下：
def binary_tree(val):
return [val, [], []]
def insert_left(root, val):
root[1] = binary_tree(val)
def insert_right(root, val):
root[2] = binary_tree(val)
def get_root_val(root):
return root[0]
def set_root_val(root, val):
root[0] = val
def get_left_child(root):
return root[1]
def get_right_child(root):
return root[2]
def preorder(root):
if root:
print(get_root_val(root))
preorder(get_left_child(root))
preorder(get_right_child(root))
def inorder(root):
if root:
inorder(get_left_child(root))
print(get_root_val(root))
inorder(get_right_child(root))
def postorder(root):
if root:
postorder(get_left_child(root))
postorder(get_right_child(root))
print(get_root_val(root))
if __name__ == '__main__':
root = binary_tree('a')
insert_left(root, 'b')
insert_right(root, 'c')
insert_right(get_left_child(root), 'd')
insert_left(get_right_child(root), 'e')
insert_right(get_right_child(root), 'f')
print(root)
# ['a',
# ['b',
# [],
# ['d', [], []]],
# ['c',
# ['e', [], []],
# ['f', [], []]]]
preorder(root) # a b d c e f
inorder(root) # b d a e c f
postorder(root) # d b e f c a