Postorder traversal
- Visit all the nodes in the left subtree
- Visit all the nodes in the right subtree
- Visit the root node
When to use? You can use post-order traversal to delete a tree, since you can delete all of a node's children before itself.
SNIPPET
1postorder(root.left)
2postorder(root.right)
3display(root.data)
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function postorderTraversal(root) { let res = []; helper(root, res); return res;}​function helper(root, res) { if (!root) { return res; } helper(root.left, res); helper(root.right, res); res.push(root.val); return res;}​const root = { val: 1, left: { val: 2 }, right: { val: 3 }};​console.log(postorderTraversal(root));OUTPUT
:001 > Cmd/Ctrl-Enter to run, Cmd/Ctrl-/ to comment