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 Object

1519 - Number of Nodes in the Sub-Tree With the Same Label.<p>Medium</p> <p>You are given a tree (i.e. a connected, undirected graph that has no cycles) consisting of <code>n</code> nodes numbered from <code>0</code> to <code>n - 1</code> and exactly <code>n - 1</code> <code>edges</code>. The <strong>root</strong> of the tree is the node <code>0</code>, and each node of the tree has <strong>a label</strong> which is a lower-case character given in the string <code>labels</code> (i.e. The node with the number <code>i</code> has the label <code>labels[i]</code>).</p> <p>The <code>edges</code> array is given on the form <code>edges[i] = [a_i, b_i]</code>, which means there is an edge between nodes <code>a_i</code> and <code>b_i</code> in the tree.</p> <p>Return <em>an array of size <code>n</code></em> where <code>ans[i]</code> is the number of nodes in the subtree of the <code>i^th</code> node which have the same label as node <code>i</code>.</p> <p>A subtree of a tree <code>T</code> is the tree consisting of a node in <code>T</code> and all of its descendant nodes.</p> <p><strong>Example 1:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2020/07/01/q3e1.jpg" alt="" /></p> <p><strong>Input:</strong> n = 7, edges = [[0,1],[0,2],[1,4],[1,5],[2,3],[2,6]], labels = &ldquo;abaedcd&rdquo;</p> <p><strong>Output:</strong> [2,1,1,1,1,1,1]</p> <p><strong>Explanation:</strong> Node 0 has label &lsquo;a&rsquo; and its sub-tree has node 2 with label &lsquo;a&rsquo; as well, thus the answer is 2. Notice that any node is part of its sub-tree.</p> <p>Node 1 has a label &lsquo;b&rsquo;. 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).</p> <p><strong>Example 2:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2020/07/01/q3e2.jpg" alt="" /></p> <p><strong>Input:</strong> n = 4, edges = [[0,1],[1,2],[0,3]], labels = &ldquo;bbbb&rdquo;</p> <p><strong>Output:</strong> [4,2,1,1]</p> <p><strong>Explanation:</strong> The sub-tree of node 2 contains only node 2, so the answer is 1.</p> <p>The sub-tree of node 3 contains only node 3, so the answer is 1.</p> <p>The sub-tree of node 1 contains nodes 1 and 2, both have label &lsquo;b&rsquo;, thus the answer is 2.</p> <p>The sub-tree of node 0 contains nodes 0, 1, 2 and 3, all with label &lsquo;b&rsquo;, thus the answer is 4.</p> <p><strong>Example 3:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2020/07/01/q3e3.jpg" alt="" /></p> <p><strong>Input:</strong> n = 5, edges = [[0,1],[0,2],[1,3],[0,4]], labels = &ldquo;aabab&rdquo;</p> <p><strong>Output:</strong> [3,2,1,1,1]</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= n <= 10⁵</code></li> <li><code>edges.length == n - 1</code></li> <li><code>edges[i].length == 2</code></li> <li><code>0 <= a_i, b_i < n</code></li> <li><code>a_i != b_i</code></li> <li><code>labels.length == n</code></li> <li><code>labels</code> is consisting of only of lowercase English letters.</li> </ul>

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

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