C++之Binary Heap/Max Heap

  1 #include <iostream>
  2 #include <time.h>
  3 #include <random>
  4
  5 using namespace std;
  6
  7 //Binary Heap; Max Heap;
  8
  9 class BinaryHeap
 10 {
 11 public:
 12     BinaryHeap();
 13     BinaryHeap(int capacity);
 14     ~BinaryHeap();
 15
 16     int insert(int value);
 17     int getIndex(int value);
 18     int removeRoot();
 19     void print();
 20     bool isEmpty();
 21
 22 private:
 23     void sortUp(int start);
 24     void sortDown(int start, int end);
 25
 26     int *heap;
 27     int capacity;
 28     int size ;
 29 };
 30
 31 BinaryHeap::BinaryHeap()
 32 {
 33     this->size = 0;
 34     this->capacity = 50;
 35     heap = new int[this->capacity];
 36 }
 37
 38 BinaryHeap::BinaryHeap(int capacity)
 39 {
 40     this->size = 0;
 41     this->capacity = capacity;
 42     heap = new int[this->capacity];
 43 }
 44
 45 BinaryHeap::~BinaryHeap()
 46 {
 47     this->size = 0;
 48     this->capacity = 0;
 49     delete[] heap;
 50 }
 51
 52 int BinaryHeap::insert(int value)
 53 {
 54
 55     if (this->size==this->capacity) //The heap is full
 56     {
 57         return -1;
 58     }
 59     heap[this->size] = value;
 60     this->sortUp(this->size);
 61     this->size++;
 62     return 0;
 63 }
 64
 65 int BinaryHeap::getIndex(int value)
 66 {
 67     for (int i = 0; i < this->size; i++)
 68     {
 69         if (value==this->heap[i])
 70         {
 71             return i;
 72         }
 73     }
 74     return -1;
 75 }
 76
 77 int BinaryHeap::removeRoot()
 78 {
 79
 80     int index = 0;
 81     if (this->size==0)
 82     {
 83         return 1;//The heap is empty
 84     }
 85
 86     this->heap[index] = this->heap[--this->size];
 87     this->sortDown(index, this->size - 1);
 88
 89     return 0;
 90 }
 91
 92 void BinaryHeap::print()
 93 {
 94     for (int i = 0; i < this->size; i++)
 95     {
 96         cout << "No." << i + 1 << " : " << heap[i] << " " << endl;;
 97     }
 98 }
 99
100
101
102 bool BinaryHeap::isEmpty()
103 {
104     if (this->size == 0)
105     {
106         return true;
107     }
108     else
109     {
110         return false;
111     }
112 }
113
114
115
116 void BinaryHeap::sortUp(int start)
117 {
118     int c = start;  //The location of current node
119     int p = (c - 1) / 2; //The location of parent node
120     int temp = heap[c]; //The value of current node
121
122     while (c>0)
123     {
124         if (heap[p] > temp)
125         {
126             break;
127         }
128         else
129         {
130             heap[c] = heap[p];
131             c = p;
132             p = (p - 1) / 2;
133         }
134     }
135     heap[c] = temp;
136 }
137
138 void BinaryHeap::sortDown(int start, int end)
139 {
140     int c=start; //the location of current node
141     int l = 2*c + 1; //The location of left child
142     int temp = heap[c]; //The value of current node
143
144     while (l <= end)
145     {
146         if (l<end && heap[l]<heap[l+1])
147         {
148             l++;  //Choose the bigger one between left child and right child
149         }
150         if (temp>=heap[l])
151         {
152             break;
153         }
154         else
155         {
156             heap[c] = heap[l];
157             c = l;
158             l = 2 * l + 1;
159         }
160     }
161     heap[c] = temp;
162 }
163
164
165 int main()
166 {
167
168
169     BinaryHeap *b = new  BinaryHeap(50);
170
171     default_random_engine random(time(NULL)); //C++ 11
172     uniform_int_distribution<int> num(0, 999);//C++ 11
173
174     cout << "Insert 50 randon number which between 0~999 " << endl ;
175     for (int i = 0; i <50; i++)
176     {
177         b->insert(num(random));
178     }
179
180     cout << "Print: " << endl;
181     b->print();
182
183     cout << endl << endl;
184     cout << "Is the heap empty? " << endl;
185     cout << boolalpha << b->isEmpty() << endl << endl;
186
187     cout << "Remove" << endl;
188     switch (int n=b->removeRoot())
189     {
190     case 0:
191         cout << "Success! The root node has been removed!" << endl; break;
192     case 1:
193         cout << "Heap is empty! " << endl; break;
194     }
195     cout << endl;
196
197     cout << "Print: " << endl;
198     b->print();
199
200
201
202     system("pause");
203     return 0;
204 }