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"title": "Number of Nodes in the Sub-Tree With the Same Label",
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"content": "<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>\n\n<p>The <code>edges</code> array is given on the form <code>edges[i] = [a<sub>i</sub>, b<sub>i</sub>]</code>, which means there is an edge between nodes <code>a<sub>i</sub></code> and <code>b<sub>i</sub></code> in the tree.</p>\n\n<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<sup>th</sup></code> node which have the same label as node <code>i</code>.</p>\n\n<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>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2020/07/01/q3e1.jpg\" style=\"width: 400px; height: 291px;\" />\n<pre>\n<strong>Input:</strong> n = 7, edges = [[0,1],[0,2],[1,4],[1,5],[2,3],[2,6]], labels = "abaedcd"\n<strong>Output:</strong> [2,1,1,1,1,1,1]\n<strong>Explanation:</strong> 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.\nNode 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).\n</pre>\n\n<p><strong>Example 2:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2020/07/01/q3e2.jpg\" style=\"width: 300px; height: 253px;\" />\n<pre>\n<strong>Input:</strong> n = 4, edges = [[0,1],[1,2],[0,3]], labels = "bbbb"\n<strong>Output:</strong> [4,2,1,1]\n<strong>Explanation:</strong> The sub-tree of node 2 contains only node 2, so the answer is 1.\nThe sub-tree of node 3 contains only node 3, so the answer is 1.\nThe sub-tree of node 1 contains nodes 1 and 2, both have label 'b', thus the answer is 2.\nThe sub-tree of node 0 contains nodes 0, 1, 2 and 3, all with label 'b', thus the answer is 4.\n</pre>\n\n<p><strong>Example 3:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2020/07/01/q3e3.jpg\" style=\"width: 300px; height: 253px;\" />\n<pre>\n<strong>Input:</strong> n = 5, edges = [[0,1],[0,2],[1,3],[0,4]], labels = "aabab"\n<strong>Output:</strong> [3,2,1,1,1]\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 <= n <= 10<sup>5</sup></code></li>\n\t<li><code>edges.length == n - 1</code></li>\n\t<li><code>edges[i].length == 2</code></li>\n\t<li><code>0 <= a<sub>i</sub>, b<sub>i</sub> < n</code></li>\n\t<li><code>a<sub>i</sub> != b<sub>i</sub></code></li>\n\t<li><code>labels.length == n</code></li>\n\t<li><code>labels</code> is consisting of only of lowercase English letters.</li>\n</ul>\n",
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"code": "class Solution {\npublic:\n vector<int> countSubTrees(int n, vector<vector<int>>& edges, string labels) {\n \n }\n};",
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"code": "class Solution(object):\n def countSubTrees(self, n, edges, labels):\n \"\"\"\n :type n: int\n :type edges: List[List[int]]\n :type labels: str\n :rtype: List[int]\n \"\"\"\n ",
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"code": "/**\n * @param {number} n\n * @param {number[][]} edges\n * @param {string} labels\n * @return {number[]}\n */\nvar countSubTrees = function(n, edges, labels) {\n \n};",
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"lang": "Rust",
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"code": "impl Solution {\n pub fn count_sub_trees(n: i32, edges: Vec<Vec<i32>>, labels: String) -> Vec<i32> {\n \n }\n}",
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"hints": [
"Start traversing the tree and each node should return a vector to its parent node.",
"The vector should be of length 26 and have the count of all the labels in the sub-tree of this node."
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