111 lines
2.5 KiB
C++
111 lines
2.5 KiB
C++
//
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// Created by PC on 25-8-9.
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//
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#ifndef MAXHEAP_H
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#define MAXHEAP_H
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#include <iostream>
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#include <vector>
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#include <bits/ostream.tcc>
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template<class T>
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class maxHeap {
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private:
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std::vector<T> data;
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int dsize;
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public:
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maxHeap() : dsize(0) {}
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~maxHeap() = default;
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bool empty() const;
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int size() const;
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void pop();
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void push(const T& x);
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T& top();
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void display();
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};
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template<class T>
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bool maxHeap<T>::empty() const {
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return data.size() == 0;
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}
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template<class T>
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int maxHeap<T>::size() const {
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return dsize;
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}
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template<class T>
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void maxHeap<T>::pop() {
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if (data.empty()) {
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std::cerr << "Empty Heap!" << std::endl;
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return;
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}
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data.at(0) = data.at(data.size() - 1);
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dsize--;
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data.pop_back();
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//正确的下沉逻辑：（记住如下写法，短小精悍
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//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
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//如果当前节点已经比这个目标大 → 停 ；否则 → 交换并继续下沉
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int index = 0;
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int left = 2 * index + 1;
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int right = 2 * index + 2;
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while (left < data.size()) {
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int largest = index;
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if (data[left] > data[largest]) largest = left;
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if (data[right] > data[largest]) largest = right;
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if (largest == index) break;
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std::swap(data[index], data[largest]);
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index = largest;
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left = 2 * index + 1;
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right = 2 * index + 2;
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}
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}
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template<class T>
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void maxHeap<T>::push(const T &x) {
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data.push_back(x); // 新元素放到末尾
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dsize++;
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int idx = dsize - 1; // 当前节点下标
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while (idx > 0) {
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int parent = (idx - 1) / 2;
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if (data[idx] > data[parent]) { // 如果比父节点大，就交换
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std::swap(data[idx], data[parent]);
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idx = parent; // 继续向上
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} else {
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break; // 满足堆性质，结束
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}
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}
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}
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template<class T>
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T & maxHeap<T>::top() {
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if (data.empty()) {
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std::cerr << "Empty Heap" << std::endl;
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}
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else {
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return data[0];
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}
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}
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template<class T>
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void maxHeap<T>::display() {
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int jmp = 1;
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int cnt = jmp;
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for (int i = 0; i < data.size(); ++i) {
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std::cout << data.at(i) << " ";
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cnt--;
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if (cnt == 0) {
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jmp *= 2;
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cnt = jmp;
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std::cout << std::endl;
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}
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}
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std::cout << std::endl << std::endl;
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}
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#endif //MAXHEAP_H
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