Package g1501_1600.s1530_number_of_good_leaf_nodes_pairs

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    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 <code>1, 2<sup>10</sup>.</code>

    • 1 &lt;= Node.val &lt;= 100

    • 1 &lt;= distance &lt;= 10

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

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

      • Methods inherited from class java.lang.Object

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