def insert2(B, x):
if B == None:
return btree.BTree([x])
else:
if B.nbkeys == 2 * B.degree - 1: # root split
B = btree.BTree([], [B])
split(B, 0)
__insert2(B, x)
return B
def insert(B, x):
'''
inserts x in B (if not already in B)
returns B (needed: in case of new root!)
'''
if B == None:
return btree.BTree([x])
else:
if B.nbkeys == 2 * B.degree - 1: # root split
B = btree.BTree([], [B])
split(B, 0)
__insert(B, x)
return B
def rbt_to_24tree(B):
if B == None:
return None
else:
N = btree.BTree([], [])
if B.left and B.left.red:
pass
else:
pass
if B.right and B.right.red:
pass
else:
pass
if N.children[0] == None: # delete the list of None in leaves!
N.children = []
return N
def split(B, i):
'''
splits the child i of B
conditions:
- B is a nonempty tree and its root is not a 2t-node.
- The child i of B exists and its root is a 2t-node.
'''
mid = B.degree - 1
L = B.children[i]
R = btree.BTree()
# keys
(L.keys, x, R.keys) = (L.keys[:mid], L.keys[mid], L.keys[mid + 1:])
# children
if L.children == []:
R.children = [] # useless L[:2] = [] if L is []!
else:
(L.children, R.children) = (L.children[:mid + 1], L.children[mid + 1:])
# root
B.keys.insert(i, x)
B.children.insert(i + 1, R)
def redBlackTo24tree(B):
if B == None:
return None
else:
N = btree.BTree()
if B.left and B.left.red:
pass
else:
pass
if B.right and B.right.red:
pass
else:
pass
if N.children[0] == None:
N.children = []
return N