堆排序

利用最小堆将数组从大到小排列

Python代码：

# -*- coding: utf-8 -*-'''堆排序'''# 从上往下调整堆，使得堆变成最小堆def filter_down(array, beg, end):    current, child = beg, 2*beg + 1    temp = array[current]    while child <= end:        if child < end and array[child] > array[child + 1]:            child += 1        if array[child] < temp:            array[current] = array[child]            current, child = child, 2*child + 1        else:            break    array[current] = temp# 堆排序，排序后的数组从大到小排列def heap_sort(array):    m = len(array) - 1    for i in range(int((m-1)/2), -1, -1):        filter_down(array, i, m)    array[0], array[m] = array[m], array[0]    for j in range(m - 1, 0, -1):        filter_down(array, 0, j)        array[0], array[j] = array[j], array[0]import randomb = [random.randint(-20, 20) for _ in range(10)]  # 在0到100中产生20个随机数print bheap_sort(b)print b

C++代码：

void swap(double &a, double &b) {double t = a;a = b;b = t;}void filter_down(double* array, int beg, int end) {double temp = array[beg];int current = beg, child = 2 * beg + 1;while (child <= end) {if (child < end && array[child + 1] < array[child])child += 1;if (temp > array[child]) {array[current] = array[child];current = child;child = 2 * child + 1;}elsebreak;}array[current] = temp;}

#include <iostream>using namespace std;#include <string>using std::string;#include "heap_sort.h"int main() {const int N = 10;double a[N] = {-10, -8, -18, 4, 17, 0, -12, -14, 10, -10};for (int i = (int)((N - 2) / 2); i >= 0; --i) filter_down(a, i, N - 1);for (int i = N - 1; i > 0; --i) {filter_down(a, 0, i);swap(a[0], a[i]);}for (int i = 0; i < N; ++i) {cout << a[i] << '\t';}cout << endl;string s;for (cin >> s; s != "c"; cin >> s)continue;return 0;}