Package g1501_1600.s1519_number_of_nodes_in_the_sub_tree_with_the_same_label

Class Solution

java.lang.Object
g1501_1600.s1519_number_of_nodes_in_the_sub_tree_with_the_same_label.Solution
public class Solution extends java.lang.Object
1519 - Number of Nodes in the Sub-Tree With the Same Label.

Medium

You are given a tree (i.e. a connected, undirected graph that has no cycles) consisting of n nodes numbered from 0 to n - 1 and exactly n - 1 edges. The root of the tree is the node 0, and each node of the tree has a label which is a lower-case character given in the string labels (i.e. The node with the number i has the label labels[i]).

The edges array is given on the form edges[i] = [ai, bi], which means there is an edge between nodes ai and bi in the tree.

Return an array of size n where ans[i] is the number of nodes in the subtree of the ith node which have the same label as node i.

A subtree of a tree T is the tree consisting of a node in T and all of its descendant nodes.

Example 1:

Input: n = 7, edges = [[0,1],[0,2],[1,4],[1,5],[2,3],[2,6]], labels = “abaedcd”

Output: [2,1,1,1,1,1,1]

Explanation: Node 0 has label ‘a’ and its sub-tree has node 2 with label ‘a’ as well, thus the answer is 2. Notice that any node is part of its sub-tree.

Node 1 has a label ‘b’. The sub-tree of node 1 contains nodes 1,4 and 5, as nodes 4 and 5 have different labels than node 1, the answer is just 1 (the node itself).

Example 2:

Input: n = 4, edges = [[0,1],[1,2],[0,3]], labels = “bbbb”

Output: [4,2,1,1]

Explanation: The sub-tree of node 2 contains only node 2, so the answer is 1.

The sub-tree of node 3 contains only node 3, so the answer is 1.

The sub-tree of node 1 contains nodes 1 and 2, both have label ‘b’, thus the answer is 2.

The sub-tree of node 0 contains nodes 0, 1, 2 and 3, all with label ‘b’, thus the answer is 4.

Example 3:

Input: n = 5, edges = [[0,1],[0,2],[1,3],[0,4]], labels = “aabab”

Output: [3,2,1,1,1]

Constraints:

  • 1 <= n <= 105
  • edges.length == n - 1
  • edges[i].length == 2
  • 0 <= ai, bi < n
  • ai != bi
  • labels.length == n
  • labels is consisting of only of lowercase English letters.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Solution()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    int[]
    countSubTrees(int n, int[][] edges, java.lang.String labelsString)
     

    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

    • countSubTrees

      public int[] countSubTrees(int n, int[][] edges, java.lang.String labelsString)