cpp-algo-cases/chapter_tree/array_binary_tree.cpp

/**
 * File: array_binary_tree.cpp
 * Created Time: 2023-07-19
 * Author: krahets (krahets@163.com)
 */

#include "../utils/common.hpp"

/* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʾ<EFBFBD>µĶ<C2B5><C4B6><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
class ArrayBinaryTree {
  public:
    /* <20><><EFBFBD>췽<EFBFBD><ECB7BD> */
    ArrayBinaryTree(vector<int> arr) {
        tree = arr;
    }

    /* <20>б<EFBFBD><D0B1><EFBFBD><EFBFBD><EFBFBD> */
    int size() {
        return tree.size();
    }

    /* <20><>ȡ<EFBFBD><C8A1><EFBFBD><EFBFBD>Ϊ i <20>ڵ<EFBFBD><DAB5><EFBFBD>ֵ */
    int val(int i) {
        // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Խ<EFBFBD>磬<EFBFBD>򷵻<EFBFBD> INT_MAX <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>λ
        if (i < 0 || i >= size())
            return INT_MAX;
        return tree[i];
    }

    /* <20><>ȡ<EFBFBD><C8A1><EFBFBD><EFBFBD>Ϊ i <20>ڵ<EFBFBD><DAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ӽڵ<D3BD><DAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
    int left(int i) {
        return 2 * i + 1;
    }

    /* <20><>ȡ<EFBFBD><C8A1><EFBFBD><EFBFBD>Ϊ i <20>ڵ<EFBFBD><DAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ӽڵ<D3BD><DAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
    int right(int i) {
        return 2 * i + 2;
    }

    /* <20><>ȡ<EFBFBD><C8A1><EFBFBD><EFBFBD>Ϊ i <20>ڵ<EFBFBD><DAB5>ĸ<EFBFBD><C4B8>ڵ<EFBFBD><DAB5><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
    int parent(int i) {
        return (i - 1) / 2;
    }

    /* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
    vector<int> levelOrder() {
        vector<int> res;
        // ֱ<>ӱ<EFBFBD><D3B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
        for (int i = 0; i < size(); i++) {
            if (val(i) != INT_MAX)
                res.push_back(val(i));
        }
        return res;
    }

    /* ǰ<><C7B0><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
    vector<int> preOrder() {
        vector<int> res;
        dfs(0, "pre", res);
        return res;
    }

    /* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
    vector<int> inOrder() {
        vector<int> res;
        dfs(0, "in", res);
        return res;
    }

    /* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
    vector<int> postOrder() {
        vector<int> res;
        dfs(0, "post", res);
        return res;
    }

  private:
    vector<int> tree;

    /* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ȱ<EFBFBD><C8B1><EFBFBD> */
    void dfs(int i, string order, vector<int> &res) {
        // <20><>Ϊ<EFBFBD><CEAA>λ<EFBFBD><CEBB><EFBFBD>򷵻<EFBFBD>
        if (val(i) == INT_MAX)
            return;
        // ǰ<><C7B0><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
        if (order == "pre")
            res.push_back(val(i));
        dfs(left(i), order, res);
        // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
        if (order == "in")
            res.push_back(val(i));
        dfs(right(i), order, res);
        // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
        if (order == "post")
            res.push_back(val(i));
    }
};

/* Driver Code */
int main() {
    // <20><>ʼ<EFBFBD><CABC><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
    // ʹ<><CAB9> INT_MAX <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>λ nullptr
    vector<int> arr = {1, 2, 3, 4, INT_MAX, 6, 7, 8, 9, INT_MAX, INT_MAX, 12, INT_MAX, INT_MAX, 15};
    TreeNode *root = vectorToTree(arr);
    cout << "\n<EFBFBD><EFBFBD>ʼ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>\n";
    cout << "<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʾ<EFBFBD><EFBFBD>\n";
    printVector(arr);
    cout << "<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʾ<EFBFBD><EFBFBD>\n";
    printTree(root);

    // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ʾ<EFBFBD>µĶ<C2B5><C4B6><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
    ArrayBinaryTree abt(arr);

    // <20><><EFBFBD>ʽڵ<CABD>
    int i = 1;
    int l = abt.left(i), r = abt.right(i), p = abt.parent(i);
    cout << "\n<EFBFBD><EFBFBD>ǰ<EFBFBD>ڵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ " << i << "<EFBFBD><EFBFBD>ֵΪ " << abt.val(i) << "\n";
    cout << "<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ӽڵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ " << l << "<EFBFBD><EFBFBD>ֵΪ " << (l != INT_MAX ? to_string(abt.val(l)) : "nullptr") << "\n";
    cout << "<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ӽڵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ " << r << "<EFBFBD><EFBFBD>ֵΪ " << (r != INT_MAX ? to_string(abt.val(r)) : "nullptr") << "\n";
    cout << "<EFBFBD>丸<EFBFBD>ڵ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ " << p << "<EFBFBD><EFBFBD>ֵΪ " << (p != INT_MAX ? to_string(abt.val(p)) : "nullptr") << "\n";

    // <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
    vector<int> res = abt.levelOrder();
    cout << "\n<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD> ";
    printVector(res);
    res = abt.preOrder();
    cout << "ǰ<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD> ";
    printVector(res);
    res = abt.inOrder();
    cout << "<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD> ";
    printVector(res);
    res = abt.postOrder();
    cout << "<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ϊ<EFBFBD><EFBFBD> ";
    printVector(res);

    return 0;
}