63 lines
2.0 KiB
C++
63 lines
2.0 KiB
C++
#include <vector>
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#include <functional>
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#include <iostream>
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/**
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* 2049. Count Nodes With the Highest Score
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* There is a binary tree rooted at 0 consisting of n nodes. The nodes are labeled from 0 to n - 1. You are given a 0-indexed integer array parents representing the tree, where parents[i] is the parent of node i. Since node 0 is the root, parents[0] == -1.
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* Each node has a score. To find the score of a node, consider if the node and the edges connected to it were removed. The tree would become one or more non-empty subtrees. The size of a subtree is the number of the nodes in it. The score of the node is the product of the sizes of all those subtrees.
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* Return the number of nodes that have the highest score.
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*/
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class Solution {
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public:
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static int countHighestScoreNodes(const std::vector<int>& parents) {
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auto n = parents.size();
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int* L = new int[n]{};
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int* R = new int[n]{};
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int* sizeOfSubtrees = new int[n]{};
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for (int i = 1; i < n; ++i)
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*(L[parents[i]] ? &R[parents[i]] : &L[parents[i]]) = i;
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std::function<int(int)> getSubtreeSize = [&](int node) {
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if (sizeOfSubtrees[node])
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return sizeOfSubtrees[node];
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int ret = 1;
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if (L[node])
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ret += getSubtreeSize(L[node]);
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if (R[node])
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ret += getSubtreeSize(R[node]);
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return sizeOfSubtrees[node] = ret;
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};
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unsigned long long retMax = 0;
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int ret = -1;
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for (int i = 0; i < n; ++i) {
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int sizeL = 0, sizeR = 0, sizeOther = n - 1;
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if (L[i])
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sizeOther -= (sizeL = getSubtreeSize(L[i]));
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if (R[i])
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sizeOther -= (sizeR = getSubtreeSize(R[i]));
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auto size = static_cast<unsigned long long>(sizeL ? sizeL : 1) * static_cast<unsigned long long>(sizeR ? sizeR : 1) * static_cast<unsigned long long>(sizeOther ? sizeOther : 1);
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if (retMax < size) {
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retMax = size;
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ret = 1;
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} else if (retMax == size) {
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++ret;
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}
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}
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delete[] L;
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delete[] R;
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delete[] sizeOfSubtrees;
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return ret;
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}
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};
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int main() {
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std::cout << Solution::countHighestScoreNodes({-1,2,0});
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return 0;
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}
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