d叉堆实现优先队列

时间复杂度 dlog（d,n)

#include <stdexcept>
#include <iostream>
class DForkHeapPriorityQueue {
private:int capacity;int *array;int d;int heap_size;
public:DForkHeapPriorityQueue(int capacity,int d);DForkHeapPriorityQueue(int* array,int length,int d);virtual ~DForkHeapPriorityQueue();void insert(int key);int extract_max();int get_heap_size();private:void increase_key(int key,int index);void build_heap();void max_heapify(int parent_index);int parent(int index);int child(int parent_index,int child_index);
};DForkHeapPriorityQueue::DForkHeapPriorityQueue(int capacity,int d):capacity(capacity),d(d){array = new int [capacity];heap_size = 0;
}
DForkHeapPriorityQueue::DForkHeapPriorityQueue(int* array,int length,int d):d(d)
{this->array = new int [length];for (int i = 0; i < length; ++i) {this->array[i] = array[i];}heap_size = length;capacity = heap_size;build_heap();
}
DForkHeapPriorityQueue::~DForkHeapPriorityQueue()
{if(array!= nullptr)delete [] array;
}
void DForkHeapPriorityQueue::insert(int key){if(heap_size >= capacity){int* temp_array = new int[capacity*2];for (int i = 0; i < capacity; ++i) {temp_array[i] = array[i];}delete [] array;array = temp_array;}heap_size++;array[heap_size-1] = INT_MIN;increase_key(heap_size-1,key);
}
int DForkHeapPriorityQueue::extract_max(){if(heap_size<=0){perror("array is empty");return -1;}int max = array[0];array[0] = array[heap_size-1];heap_size--;max_heapify(0);return max;
}void DForkHeapPriorityQueue::increase_key(int key,int index){if(array[index] > key){perror("new key is underflow");return;}array[index] = key;while (index > 0 && array[parent(index)] < key){array[index] = array[parent(index)];array[parent(index)] = key;index = parent(index);}
}
void DForkHeapPriorityQueue::build_heap(){for (int i = heap_size/2; i >=0; i--) {max_heapify(i);}
}
void DForkHeapPriorityQueue::max_heapify(int parent_index){int largest = parent_index;int current_child_index = 0;while (current_child_index<d){int index = child(parent_index,current_child_index);if(index >= heap_size) break;if(array[index] > array[largest])largest = index;current_child_index++;}if(largest != parent_index){int temp = array[largest];array[largest] = array[parent_index];array[parent_index] = temp;max_heapify(largest);}
}
int DForkHeapPriorityQueue::parent(int index){return (index - 1) / d;
}
int DForkHeapPriorityQueue::child(int parent_index,int child_index){return parent_index * d + child_index + 1;
}
int DForkHeapPriorityQueue::get_heap_size(){return heap_size;
}