Priority_Queue C++
优先队列:
是计算机科学中的一类抽象数据类型。优先队列中的每个元素都有各自的优先级，优先级最高的元素最先得到服务；优先级相同的元素按照其在优先队列中的顺序得到服务。优先队列往往用堆来实现。
1 #pragma once 2 #include<vector> 3 #include<stdexcept>//runtime_error 4 #include<iostream> 5 #include"HEAPSORT.h" 6 7 int Heap_Maximum(std::vector<int>& A) 8 { 9 return A[0]; 10 } 11 12 13 //取最大值并删除 14 int Heap_Extract_Max(std::vector<int>& A) 15 { 16 heap_size = A.size() - 1; 17 Build_Max_Heap(A); 18 /* 19 try 20 { 21 if (heap_size < 0) 22 throw std::runtime_error("heap underflow"); 23 } 24 catch (std::runtime_error err) 25 { 26 std::cout << err.what() 27 << "\n Try Again? Enter y or n" << std::endl; 28 char c; 29 std::cin >> c; 30 if (!std::cin || c == 'n') 31 return -1; 32 } 33 */ 34 if (heap_size < 0) 35 throw std::runtime_error("heap underflow"); 36 int max = A[0]; 37 A[0] = A[heap_size]; 38 --heap_size; 39 Max_Heapify(A, 0); 40 return max; 41 } 42 //改变(变大)节点里面的值 43 void Heap_Increase_Key(std::vector<int>& A, int& i, const int& key) 44 { 45 if (key < A[i]) 46 throw std::runtime_error("new key is small than current key"); 47 A[i] = key; 48 //保持最大堆 49 while (i > 0 && A[parent(i)] < A[i]) 50 { 51 std::swap(A[i], A[parent(i)]); 52 i = parent(i); 53 } 54 } 55 //在末尾处插入键值 56 void Max_Heap_Insert(std::vector<int>& A, const int& key) 57 { 58 ++heap_size; 59 A[heap_size] = INT_MIN; 60 Heap_Increase_Key(A, heap_size, key); 61 }
main.cpp
1 #include<iostream> 2 #include<iterator> //ostream_iterator 3 #include"PRIORITY_QUEUE.h" 4 using namespace std; 5 void print(vector<int>& v) 6 { 7 ostream_iterator<int> out_iter(cout, " "); 8 copy(v.begin(), v.end(), out_iter); 9 } 10 void Priority_Queue() 11 { 12 vector<int> v = { 4,1,3,2,16,9,10,14,8,7 }; 13 print(v); 14 cout << endl; 15 cout << Heap_Extract_Max(v) << endl; 16 Max_Heap_Insert(v, 15); 17 cout<<Heap_Maximum(v) << endl; 18 HeapSort(v); 19 print(v); 20 } 21 int main() 22 { 23 Priority_Queue(); 24 }
