#814

Binary Tree Pruning

pupil · 520 · lc medium +28 · verified · 72.5% accepted · 4,664 likes · top 82%

Description

Given the root of a binary tree, remove every subtree that does not contain a 1, and return the modified tree.

A subtree rooted at a given node consists of that node and all of its descendants.

Example 1:

Input: root = [1,null,0,0,1]
Output: [1,null,0,null,1]
Explanation:
Only the red nodes satisfy the property "every subtree not containing a 1".
The diagram on the right represents the answer.

Example 2:

Input: root = [1,0,1,0,0,0,1]
Output: [1,null,1,null,1]

Example 3:

Input: root = [1,1,0,1,1,0,1,0]
Output: [1,1,0,1,1,null,1]

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