Package g0501_0600.s0563_binary_tree_tilt

Class Solution

java.lang.Object
g0501_0600.s0563_binary_tree_tilt.Solution
public class Solution extends java.lang.Object
563 - Binary Tree Tilt.

Easy

Given the root of a binary tree, return the sum of every tree node’s tilt.

The tilt of a tree node is the absolute difference between the sum of all left subtree node values and all right subtree node values. If a node does not have a left child, then the sum of the left subtree node values is treated as 0. The rule is similar if the node does not have a right child.

Example 1:

Input: root = [1,2,3]

Output: 1

Explanation:

 Tilt of node 2 : |0-0| = 0 (no children)
 Tilt of node 3 : |0-0| = 0 (no children)
 Tilt of node 1 : |2-3| = 1 (left subtree is just left child, so sum is 2; right subtree is just right child, so sum is 3) 
 Sum of every tilt : 0 + 0 + 1 = 1

Example 2:

Input: root = [4,2,9,3,5,null,7]

Output: 15

Explanation:

 Tilt of node 3 : |0-0| = 0 (no children) 
 Tilt of node 5 : |0-0| = 0 (no children) 
 Tilt of node 7 : |0-0| = 0 (no children) 
 Tilt of node 2 : |3-5| = 2 (left subtree is just left child, so sum is 3; right subtree is just right child, so sum is 5) 
 Tilt of node 9 : |0-7| = 7 (no left child, so sum is 0; right subtree is just right child, so sum is 7) 
 Tilt of node 4 : |(3+5+2)-(9+7)| = |10-16| = 6 (left subtree values are 3, 5, and 2, which sums to 10; right subtree values are 9 and 7, which sums to 16) 
 Sum of every tilt : 0 + 0 + 0 + 2 + 7 + 6 = 15

Example 3:

Input: root = [21,7,14,1,1,2,2,3,3]

Output: 9

Constraints:

  • The number of nodes in the tree is in the range [0, 104].
  • -1000 <= Node.val <= 1000

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    findTilt(TreeNode root)
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • findTilt

      public int findTilt(TreeNode root)