Git-Mirrors/master-algorithms-py
1
0
Fork 0
mirror of https://github.com/autistic-symposium/master-algorithms-py.git synced 2025-04-29 12:16:14 -04:00
Code Issues Packages Projects Releases Wiki Activity

Update bt_construct_inorder_preorder.py

Browse Source
This commit is contained in:
bt3gl 2023-08-08 19:56:03 -07:00 committed by GitHub
parent 14404c47c8
commit fcd4eb423b
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 5 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
trees/bt_construct_inorder_preorder.py
View File

@ -3,15 +3,16 @@
# author: bt3gl # author: bt3gl
def build_tree(preorder, inorder) -> Optional[Node]: def build_tree(preorder, inorder):
def helper(left, right, index_map): def helper(left, right, index_map):
if left > right: if left > right:
return None return None
root = Node(preorder.pop(0)) # # this order change from postorder node = preorder.pop(0) # this order change from postorder
index_here = index_map[root.val] root = Node(node.val)
index_here = index_map[node.val]
root.left = helper(left, index_here - 1, index_map) # this order change from postorder root.left = helper(left, index_here - 1, index_map) # this order change from postorder
root.right = helper(index_here + 1, right, index_map) root.right = helper(index_here + 1, right, index_map)