Package g1501_1600.s1530_number_of_good_leaf_nodes_pairs

Class Solution

java.lang.Object
g1501_1600.s1530_number_of_good_leaf_nodes_pairs.Solution
public class Solution extends java.lang.Object
1530 - Number of Good Leaf Nodes Pairs.

Medium

You are given the root of a binary tree and an integer distance. A pair of two different leaf nodes of a binary tree is said to be good if the length of the shortest path between them is less than or equal to distance.

Return the number of good leaf node pairs in the tree.

Example 1:

Input: root = [1,2,3,null,4], distance = 3

Output: 1

Explanation: The leaf nodes of the tree are 3 and 4 and the length of the shortest path between them is 3. This is the only good pair.

Example 2:

Input: root = [1,2,3,4,5,6,7], distance = 3

Output: 2

Explanation: The good pairs are [4,5] and [6,7] with shortest path = 2. The pair [4,6] is not good because the length of ther shortest path between them is 4.

Example 3:

Input: root = [7,1,4,6,null,5,3,null,null,null,null,null,2], distance = 3

Output: 1

Explanation: The only good pair is [2,5].

Constraints:

  • The number of nodes in the tree is in the range [1, 210].
  • 1 <= Node.val <= 100
  • 1 <= distance <= 10

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    countPairs(TreeNode root, int distance)
     

    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

    • countPairs

      public int countPairs(TreeNode root, int distance)