43 lines
1.1 KiB
C++
43 lines
1.1 KiB
C++
#include <vector>
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struct TreeNode {
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int val;
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TreeNode* left;
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TreeNode* right;
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explicit TreeNode(int x, TreeNode* left = nullptr, TreeNode* right = nullptr) : val(x), left(left), right(right) {}
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};
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/**
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* 106. Construct Binary Tree from Inorder and Postorder Traversal
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*
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* Given two integer arrays inorder and postorder where inorder is the inorder traversal of a binary tree and postorder is the postorder traversal of the same tree, construct and return the binary tree.
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*/
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using VCI = std::vector<int>::const_iterator;
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class Solution {
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private:
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static TreeNode* bT(VCI is, VCI ie, VCI ps, VCI pe) {
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if (is == ie || ps == pe)
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return nullptr;
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int r = *(pe - 1);
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int pos = std::find(is, ie, r) - is;
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return new TreeNode(
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r,
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bT(is, is + pos, ps, ps + pos),
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bT(is + pos + 1, ie, ps + pos, pe - 1)
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);
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}
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public:
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static TreeNode* buildTree(const std::vector<int>& inorder, const std::vector<int>& postorder) {
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return bT(inorder.begin(), inorder.end(), postorder.begin(), postorder.end());
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}
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};
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int main() {
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Solution::buildTree({-1}, {-1});
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return 0;
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}
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