//
// Created by PC on 25-8-9.
//

#ifndef MAXHEAP_H
#define MAXHEAP_H
#include <iostream>
#include <vector>
#include <bits/ostream.tcc>

template<class T>
class maxHeap {
private:
    std::vector<T> data;
    int dsize;
public:
    maxHeap() : dsize(0) {}
    ~maxHeap() = default;

    bool empty() const;
    int size() const;
    void pop();
    void push(const T& x);
    T& top();
    void display();
};

template<class T>
bool maxHeap<T>::empty() const {
    return data.size() == 0;
}

template<class T>
int maxHeap<T>::size() const {
    return dsize;
}

template<class T>
void maxHeap<T>::pop() {
    if (data.empty()) {
        std::cerr << "Empty Heap!" << std::endl;
        return;
    }
    data.at(0) = data.at(data.size() - 1);
    dsize--;
    data.pop_back();
    //正确的下沉逻辑：（记住如下写法，短小精悍
    //先找左节点（如果有）再找右节点（如果有）比较左右节点，选择更大的那个作为可能交换的目标
    //如果当前节点已经比这个目标大 → 停 ；否则 → 交换并继续下沉
    int index = 0;
    int left = 2 * index + 1;
    int right = 2 * index + 2;
    while (left < data.size()) {
        int largest = index;
        if (data[left] > data[largest]) largest = left;
        if (data[right] > data[largest]) largest = right;
        if (largest == index) break;

        std::swap(data[index], data[largest]);
        index = largest;
        left = 2 * index + 1;
        right = 2 * index + 2;
    }
}

template<class T>
void maxHeap<T>::push(const T &x) {
    data.push_back(x); // 新元素放到末尾
    dsize++;

    int idx = dsize - 1; // 当前节点下标
    while (idx > 0) {
        int parent = (idx - 1) / 2;
        if (data[idx] > data[parent]) { // 如果比父节点大，就交换
            std::swap(data[idx], data[parent]);
            idx = parent; // 继续向上
        } else {
            break; // 满足堆性质，结束
        }
    }
}


template<class T>
T & maxHeap<T>::top() {
    if (data.empty()) {
        std::cerr << "Empty Heap" << std::endl;
    }
    else {
        return data[0];
    }
}

template<class T>
void maxHeap<T>::display() {
    int jmp = 1;
    int cnt = jmp;
    for (int i = 0; i < data.size(); ++i) {
        std::cout << data.at(i) << " ";
        cnt--;
        if (cnt == 0) {
            jmp *= 2;
            cnt = jmp;
            std::cout << std::endl;
        }
    }
    std::cout << std::endl << std::endl;
}

#endif //MAXHEAP_H