堆排序 

 1 /**
 2  * 排序算法之堆排序
 3 **/
 4 #include <iostream>
 5 #include <cstdio>
 6 #include <cstring>
 7 #include <algorithm>
 8 #include <vector>
 9 using namespace std;
10 
11 void adjust(vector<int>& vec, int len, int index) {
12     int left = 2 * index + 1;
13     int right = 2 * index + 2;
14     int maxIdx = index; //代表父子三个数中最大数的下标
15     if (left < len && vec[left] > vec[maxIdx]) maxIdx = left;
16     if (right < len && vec[right] > vec[maxIdx]) maxIdx = right;
17     if (maxIdx != index) {
18         swap(vec[maxIdx], vec[index]);
19         adjust(vec, len, maxIdx);
20     }
21 
22 }
23 
24 void heapSort(vector<int>& vec, int size) {
25     for (int i = size / 2 - 1; i >= 0; i--) {//从最后一个非叶节点开始进行堆调整
26         adjust(vec, size, i);
27     }
28 
29     for (int i = size - 1; i >= 1; i--) {
30         swap(vec[0], vec[i]);
31         adjust(vec, i, 0);
32     }
33 
34 }
35 
36 int main() {
37     vector<int> vec = {2,1,3,5,4};
38     int len = vec.size();
39     heapSort(vec, len);
40     for (auto x : vec) {
41         cout << x << endl;
42     }
43     return 0;
44 }

 

posted on 2018-03-07 20:03  狗剩的美丽家园  阅读(107)  评论(0)    收藏  举报

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