Package g3201_3300.s3249_count_the_number_of_good_nodes

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    3249 - Count the Number of Good Nodes.

    Medium

    There is an undirected tree with n nodes labeled from 0 to n - 1, and rooted at node 0. You are given a 2D integer array edges of length n - 1, where <code>edgesi = a<sub>i</sub>, b<sub>i</sub></code> indicates that there is an edge between nodes <code>a<sub>i</sub></code> and <code>b<sub>i</sub></code> in the tree.

    A node is good if all the subtrees rooted at its children have the same size.

    Return the number of good nodes in the given tree.

    A subtree of treeName is a tree consisting of a node in treeName and all of its descendants.

    Example 1:

    Input: edges = [0,1,0,2,1,3,1,4,2,5,2,6]

    Output: 7

    Explanation:

    All of the nodes of the given tree are good.

    Example 2:

    Input: edges = [0,1,1,2,2,3,3,4,0,5,1,6,2,7,3,8]

    Output: 6

    Explanation:

    There are 6 good nodes in the given tree. They are colored in the image above.

    Example 3:

    Input: edges = [0,1,1,2,1,3,1,4,0,5,5,6,6,7,7,8,0,9,9,10,9,12,10,11]

    Output: 12

    Explanation:

    All nodes except node 9 are good.

    Constraints:

    • <code>2 <= n <= 10<sup>5</sup></code>

    • edges.length == n - 1

    • edges[i].length == 2

    • <code>0 <= a<sub>i</sub>, b<sub>i</sub>< n</code>

    • The input is generated such that edges represents a valid tree.

    • 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 countGoodNodes(Array<IntArray> edges)

      • Methods inherited from class java.lang.Object

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