SharedSchoolSpace/作业/数据结构-金健/C++/第八章作业/第八章作业2.cpp

// 20:50
// 22:31

#include <iostream>

const int N = 1000;

class BigHeap {
private:
    int *_internal_array;
    int len = 0;
    bool external = false;

    int get_left_child(int index) {
        return this->_internal_array[index * 2];
    }

    int get_right_child(int index) {
        return this->_internal_array[index * 2 + 1];
    }

    int get_parent(int index) {
        return this->_internal_array[index / 2];
    }
    void adjust_up(int index) {
        while (index > 1 && this->_internal_array[index] > this->get_parent(index)) {
            std::swap(this->_internal_array[index], this->_internal_array[index / 2]);
            index /= 2;
        }
    }

    void adjust_down(int index) {
        while (index * 2 <= this->len) {
            int target = index;
            if (this->_internal_array[target] < this->get_left_child(index))                                // 如果左节点更大
                target = index * 2;                                                                         // 左节点换上来
            if (index * 2 + 1 <= this->len && this->_internal_array[target] < this->get_right_child(index)) // 如果右节点更大
                target = index * 2 + 1;                                                                     // 右节点换上来
            if (index == target)
                break;
            // 如果满足了当前节点比左右子节点大，就不用继续下沉了

            std::swap(this->_internal_array[index], this->_internal_array[target]);
            index = target;
        }
    }
    // 好像不太对，算了不用了，叶子节点直接判断就行了
    int get_last_non_leaf_index(int len) {
        int pow_of_2 = 1;
        int times = 0;
        while (pow_of_2 < len) {
            pow_of_2 *= 2; // 也可以写成 pow_of_2 <<= 2;
            times++;
        }
        return times;
    }

public:
    BigHeap() { // 构造函数，在初始化时被调用
        this->_internal_array = new int[N];
    }
    BigHeap(int *external_array, int len) { // 也是构造函数，但是使用外部的数组初始化，数组要从1开始
        this->_internal_array = external_array;
        this->len = len;
        for (int i = this->len; i >= 1; i--) {
            adjust_down(i);
        }
        this->external = true;
    }
    ~BigHeap() { // 析构函数，在对象被删除时被调用
        if (!this->external)
            delete this->_internal_array;
    }

    int get_length() {
        return this->len;
    }

    void insert(int num) {
        this->_internal_array[++this->len] = num;
        int index = this->len;
        adjust_up(index);
    }

    int pop() {
        int result = this->_internal_array[1];
        this->_internal_array[1] = this->_internal_array[this->len--];
        adjust_down(1);
        return result;
    }
};

int a[N];
int len;

int main() {
    std::cin >> len;
    for (int i = 1; i <= len; i++)
        std::cin >> a[i];

    BigHeap big_heap_internal;
    for (int i = 1; i <= len; i++) {
        big_heap_internal.insert(a[i]);
    }
    std::cout << "逐个插入后，逐个弹出输出的结果为：" << std::endl;
    while (big_heap_internal.get_length() > 0) {
        std::cout << big_heap_internal.pop() << " ";
    }
    std::cout << std::endl;

    BigHeap big_heap_external(a, len);
    std::cout << "一次性初始化后，逐个弹出输出的结果为：" << std::endl;
    while (big_heap_external.get_length() > 0) {
        std::cout << big_heap_external.pop() << " ";
    }
    std::cout << std::endl;
    return 0;
}