| 1 | class BST: |
| 2 | |
| 3 | def __init__(self,val,left,right): |
| 4 | self.val = val |
| 5 | self.left = left |
| 6 | self.right = right |
| 7 | |
| 8 | def addHelper(self,root,data): |
| 9 | |
| 10 | # case for reaching current leafs, base cases |
| 11 | if root.val < data and root.right == None: |
| 12 | root.right = BST(data,None,None) |
| 13 | return "insertion completed" |
| 14 | elif root.val > data and root.left == None: |
| 15 | root.left = BST(data,None,None) |
| 16 | return "insertion completed" |
| 17 | |
| 18 | # else we continue tracing downwards |
| 19 | if root.val < data: |
| 20 | return self.add(root.right,data) |
| 21 | elif root.val > data: |
| 22 | return self.add(root.left,data) |
| 23 | else: |
| 24 | return "insertion failed: duplicate value" |
| 25 | |
| 26 | def add(self,root,data): |
| 27 | if root == None: |
| 28 | return "insertion failed: empty root" |
| 29 | return self.addHelper(root,data) |
| 30 | |
| 31 | def restructdata(self,root): |
| 32 | # base case: we reach a leaf |
| 33 | if root == None or (root.left == None and root.right == None): |
| 34 | root = None |
| 35 | return "restructure finished" |
| 36 | |
| 37 | # need dummy nodes to compare target value to children value |
| 38 | v1 = float('-inf') |
| 39 | v2 = float('inf') |
| 40 | if root.left != None: |
| 41 | v1 = root.left.val |
| 42 | if root.right != None: |
| 43 | v2 = root.right.val |
| 44 | |
| 45 | temp = root.val |
| 46 | if v1 > v2 or v2 == float('inf'): |
| 47 | root.val = root.left.val |
| 48 | root.left.val = temp |
| 49 | return self.restructdata(root.left) |
| 50 | else: |
| 51 | root.val = root.right.val |
| 52 | root.right.val = temp |
| 53 | return self.restructdata(root.right) |
| 54 | |
| 55 | |
| 56 | def removeHelper(self,root,data): |
| 57 | if root == None: |
| 58 | return "deletion failed: could not find value" |
| 59 | |
| 60 | # adhering to typical bst properties |