g1401_1500.s1457_pseudo_palindromic_paths_in_a_binary_tree

Class Solution

java.lang.Object

g1401_1500.s1457_pseudo_palindromic_paths_in_a_binary_tree.Solution

public class Solution
extends Object

1457 - Pseudo-Palindromic Paths in a Binary Tree.

Medium

Given a binary tree where node values are digits from 1 to 9. A path in the binary tree is said to be pseudo-palindromic if at least one permutation of the node values in the path is a palindrome.

Return the number of pseudo-palindromic paths going from the root node to leaf nodes.

Example 1:

Input: root = [2,3,1,3,1,null,1]

Output: 2

Explanation: The figure above represents the given binary tree. There are three paths going from the root node to leaf nodes: the red path [2,3,3], the green path [2,1,1], and the path [2,3,1]. Among these paths only red path and green path are pseudo-palindromic paths since the red path [2,3,3] can be rearranged in 3,2,3 and the green path [2,1,1] can be rearranged in 1,2,1.

Example 2:

Input: root = [2,1,1,1,3,null,null,null,null,null,1]

Output: 1

Explanation: The figure above represents the given binary tree. There are three paths going from the root node to leaf nodes: the green path [2,1,1], the path [2,1,3,1], and the path [2,1]. Among these paths only the green path is pseudo-palindromic since [2,1,1] can be rearranged in 1,2,1.

Example 3:

Input: root = [9]

Output: 1

Constraints:

• The number of nodes in the tree is in the range [1, 105].
• 1 <= Node.val <= 9

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	pseudoPalindromicPaths(TreeNode root)

Methods inherited from class java.lang.Object

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

Constructor Detail

Solution

public Solution()

Method Detail

pseudoPalindromicPaths

public int pseudoPalindromicPaths(TreeNode root)