Function buildBinaryTree

cpp/Trees/build_binary_tree.cpp:17–26

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TreeNode* buildBinaryTree(std::vector<int>& preorder, std::vector<int>& inorder) {
    // Populate the hash map with the inorder values and their indexes.
    std::unordered_map<int, int> inorderIndexesMap;
    for (int i = 0; i < inorder.size(); i++) {
        inorderIndexesMap[inorder[i]] = i;
    }
    // Build the tree and return its root node.
    int preorderIndex = 0;
    return buildSubtree(0, inorder.size() - 1, preorder, inorder, preorderIndex, inorderIndexesMap);
}

TreeNode* buildSubtree(int left, int right, std::vector<int>& preorder, std::vector<int>& inorder,
                       int& preorderIndex, std::unordered_map<int, int>& inorderIndexesMap) {