c++ priority_queue
1、默认为大顶堆
1 #include <iostream> 2 #include <queue> 3 using namespace std; 4 5 int main() 6 { 7 priority_queue<int> p; 8 int i; 9 for (i = 0; i < 5; i++) 10 p.push(i); 11 for (i = 0; i < 5; i++) 12 { 13 cout << p.top() << " "; 14 p.pop(); 15 } 16 return 0; 17 }
运行结果：
2、小顶堆
1 int main() 2 { 3 priority_queue<int, vector<int>, greater<int>> p; 4 //vs2013需要#include <functional> 5 int i; 6 for (i = 0; i < 5; i++) 7 p.push(i); 8 for (i = 0; i < 5; i++) 9 { 10 cout << p.top() << " "; 11 p.pop(); 12 } 13 return 0; 14 }
运行结果：
3、自定义
1 #include <iostream> 2 #include <queue> 3 using namespace std; 4 5 struct Node 6 { 7 int a, b; 8 Node(int x, int y) : a(x), b(y) {} 9 }; 10 11 struct cmp 12 { 13 bool operator() (Node *x, Node *y) 14 { 15 if (x->a != y->a) return x->a < y->a; //大顶堆 16 return x->b < y->b; 17 } 18 }; 19 int main() 20 { 21 22 priority_queue<Node *, vector<Node *>, cmp> p; 23 Node *n = new Node(1, 2); p.push(n); 24 n = new Node(1, 3); p.push(n); 25 n = new Node(2, 3); p.push(n); 26 while (!p.empty()) 27 { 28 n = p.top(); 29 p.pop(); 30 cout << n->a << " " << n->b << endl; 31 } 32 return 0; 33 }
运行结果：
