参考：白话经典算法系列之七 堆与堆排序
1 #include <iostream>
2 #include <climits>
3 #include <vector>
4 using namespace std;
5
6 namespace heap {
7
8 //insert an element to a heap
9 void insertToHeap(vector<int>& h, int x) {
10 h.push_back(x);
11 int n = h.size();
12
13 int i = n - 1;
14 int p = (i - 1) / 2; //parent
15 int temp = x;
16 while (p >= 0 && i != 0) {
17 if (h[p] <= temp) {
18 break;
19 }
20 h[i] = h[p];
21 i = p;
22 p = (i - 1) / 2;
23 }
24 h[i] = temp;
25 }
26
27 void minHeapFixdown(vector<int>& h, int i, int n) {
28 int tmp = h[i];
29 int j = 2 * i + 1;
30 while (j < n) {
31 if (j + 1 < n && h[j + 1] < h[j]) {
32 j++;
33 }
34 if (h[j] >= tmp) {
35 break;
36 }
37 h[i] = h[j];
38 i = j;
39 j = 2 * i + 1;
40 }
41 h[i] = tmp;
42 }
43
44 //delete an element from a heap
45 void deleteFromHeap(vector<int>& h) {
46 if (h.empty())
47 return;
48 if (h.size() == 1) {
49 h.clear();
50 return;
51 }
52 int n = h.size();
53 h[0] = h[n - 1];
54 h.erase(h.end() - 1);
55 minHeapFixdown(h, 0, n);
56 }
57
58 //make an array Minimum heap
59 void heapArray(vector<int>& h) {
60 int n = h.size();
61 for (int i = n / 2 - 1; i >= 0; i--) {
62 minHeapFixdown(h, i, n);
63 }
64 }
65
66 void heapSort(vector<int>& h) {
67 int n = h.size();
68 vector<int> tmp = h;
69 for (int i = 0; i < n; i++) {
70 h[i] = tmp[0];
71 deleteFromHeap(tmp);
72 }
73 }
74
75 void printHeap(vector<int>& testVec) {
76 for (size_t i = 0; i < testVec.size(); i++) {
77 std::cout << testVec[i] << ",";
78 }
79 std::cout << std::endl;
80 }
81 }
82 ;
83
84 int main() {
85 vector<int> testVec = { 0, 3, 9, 1, 3, 5 };
86 heap::heapArray(testVec);
87 heap::printHeap(testVec);
88
89 heap::deleteFromHeap(testVec);
90 heap::printHeap(testVec);
91
92 heap::insertToHeap(testVec, 4);
93 heap::printHeap(testVec);
94
95 heap::heapSort(testVec);
96 heap::printHeap(testVec);
97
98 return 0;
99 }
