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deleteNode.py
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32 lines (29 loc) · 1.04 KB
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"""
case 1: if node we want to delete has no children: simply delete it
case 2: if it has only one child, then replace it with its child
case 3: if it has two children, first find the inorder successor (or predecessor),
then replace the node's value with successor's value, and finally delete this successor
"""
def deleteNode(self, root, key):
if not root: return None
if key < root.val:
root.left = self.deleteNode(root.left, key)
elif key > root.val:
root.right = self.deleteNode(root.right, key)
else:
# if this node has only one child or no child:
if not root.left:
temp = root.right
root = None
return temp
elif not root.right:
temp = root.left
root = None
return temp
# otherwise, find the inorder successor:
curr = root.right
while curr.left:
curr = curr.left
root.val = curr.val
root.right = self.deleteNode(root.right, curr.val)
return root