堆

今天刚刚学习堆和堆排，先手抄了一遍算法书，再自己实现一遍，作为巩固。

update : 早上起床把小根堆写了一遍 = 。 = 

 1 /*  小根堆  */
 2 #include <iostream>
 3 #include <vector>
 4 using namespace std;
 5 void downAdjust(int to_adjust,int bound,vector<int> & heap){
 6     int i = to_adjust, j = i * 2;
 7     while(j <= bound){
 8         if(j + 1 <= bound and heap[j] > heap[j+1]){
 9             j = j + 1;
10         }
11         if(heap[i] > heap[j]){
12             swap(heap[i], heap[j]);
13             i = j;
14             j = i*2;
15         }else break;
16     }
17 }
18 void upAdjust(int to_adjust,vector<int> & heap){
19     int i = to_adjust, j = i/2;
20     while(j >= 1){
21         if(heap[i] < heap[j]){
22             swap(heap[i], heap[j]);
23             i = j;
24             j = i/2;
25         }else break;
26     }
27 }
28 void insert(int v,vector<int> & heap){
29     heap.push_back(v);
30     int s = (int)heap.size()-1;
31     upAdjust(s, heap);
32 }
33 void pop(vector<int>& heap){
34     swap(heap[1], heap.back());
35     heap.pop_back();
36     int s = (int)heap.size() - 1;
37     downAdjust(1,s,heap);
38 }
39 void create_heap(vector<int>&heap){
40     int s = (int)heap.size()-1;
41     for(int i = s/2; i >= 1; i--){
42         downAdjust(i, s, heap);
43     }
44 }
45 void heapSort(vector<int>& heap){
46     create_heap(heap);
47     for(int s = (int)heap.size()-1; s > 1; s--){
48         swap(heap[1], heap[s]);
49         downAdjust(1,s-1, heap);
50     }
51 }
52 int main(){
53     vector<int> test = {-1,2,4,1,5,23,56,75,32,134,5435,31,1,3412,45,9};
54     heapSort(test);
55     for(vector<int>::iterator it = test.begin(); it not_eq test.end(); it++)cout<<*it<<" ";
56     return 0;
57 }

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 1 /*    大根堆    */
 2 #include <iostream>
 3 #include <vector>
 4 #define Maxsize    1000 + 1
 5 using namespace std;
 6 void downAdjust(int low,int high,vector<int>& Heap){
 7     int i = low, j = i * 2; //  i 是将要下调的结点 , j 是i的左结点
 8     while( j <= high ){ // 存在孩子结点
 9         if(j + 1 <= high and Heap[j] < Heap[j+1]){
10             j = j + 1;
11         }
12         if(Heap[i] < Heap[j]){
13             swap(Heap[i],Heap[j]);
14             i = j;
15             j = i*2;
16         }else break;
17     }
18 }
19 void creatHeap(vector<int>& Heap){
20     int s = (int)Heap.size() - 1;
21     for(int i = s/2; i >= 1; i--){
22         downAdjust(i, s, Heap);
23         // 不需要考虑最底层的结点, 直接从次底层开始,从下向上遍历调整。
24         // 为什么不从堆顶向下调整呢？
25         //如果从堆顶调整, 对于一个结点,在调整其子结点的步骤中可能会破坏该节点的局部大根堆结构,导致建立堆错误。
26     }
27 }
28 void pop(vector<int>& Heap){
29     int s = (int)Heap.size() - 1;
30     swap(Heap[1], Heap[s]);
31     Heap.pop_back();
32     downAdjust(1, s-1, Heap);
33 }
34 void upAdjust(int high,vector<int>& Heap){
35     int i = high, j = high/2;
36     while( j >= 1){
37         if(Heap[i] > Heap[j]){
38             swap(Heap[i], Heap[j]);
39             i = j;
40             j = i/2;
41         }else break;
42     }
43 }
44 void insert(vector<int>&Heap,int value){
45     Heap.push_back(value);
46     int s = (int)Heap.size() - 1;
47     upAdjust(s, Heap);
48 }
49 void HeapSort(vector<int>& Heap){
50     creatHeap(Heap);
51     for(int s = (int)Heap.size() - 1; s > 1; s--){
52         swap(Heap[1], Heap[s]);
53         downAdjust(1, s-1, Heap);
54     }
55 }
56 int main(){
57     vector<int> test = {0,1,314,41,2,1,3,14,14,3,11313,134}; // 0 是占位符
58     HeapSort(test);
59     for(vector<int> :: iterator it = test.begin() + 1; it not_eq test.end(); it++)cout<<*it<<" ";
60     return 0;
61 }

posted @ 2019-12-31 22:16  popozyl  阅读(197)  评论(0)  编辑  收藏  举报