/*优先队列的根本应用 */#include<stdio.h>#include<functional>#include<queue>#include<vector>using namespace std;//定义构造，应用运算符重载,自定义优先级1struct cmp1{ bool operator ()(int &a,int &b){ return a>b;//最小值优先 }};struct cmp2{ bool operator ()(int &a,int &b){ return a<b;//最大值优先 }};//定义构造，应用运算符重载,自定义优先级2struct number1{ int x; bool operator < (const number1 &a) const { return x>a.x;//最小值优先 }};struct number2{ int x; bool operator < (const number2 &a) const { return x<a.x;//最大值优先 }};int a[]={14,10,56,7,83,22,36,91,3,47,72,0};number1 num1[]={14,10,56,7,83,22,36,91,3,47,72,0};number2 num2[]={14,10,56,7,83,22,36,91,3,47,72,0};int main(){ priority_queue<int>que;//采纳默认优先级结构队列 priority_queue<int,vector<int>,cmp1>que1;//最小值优先 priority_queue<int,vector<int>,cmp2>que2;//最大值优先 priority_queue<int,vector<int>,greater<int> >que3;//留神“>>”会被认为谬误， //这是右移运算符，所以这里用空格号隔开 priority_queue<int,vector<int>,less<int> >que4;////最大值优先 priority_queue<number1>que5; priority_queue<number2>que6; int i; for(i=0;a[i];i++){ que.push(a[i]); que1.push(a[i]); que2.push(a[i]); que3.push(a[i]); que4.push(a[i]); } for(i=0;num1[i].x;i++) que5.push(num1[i]); for(i=0;num2[i].x;i++) que6.push(num2[i]); printf("采纳默认优先关系:\n(priority_queue<int>que;)\n"); printf("Queue 0:\n"); while(!que.empty()){ printf("%3d",que.top()); que.pop(); } puts(""); puts(""); printf("采纳构造体自定义优先级形式一:\n(priority_queue<int,vector<int>,cmp>que;)\n"); printf("Queue 1:\n"); while(!que1.empty()){ printf("%3d",que1.top()); que1.pop(); } puts(""); printf("Queue 2:\n"); while(!que2.empty()){ printf("%3d",que2.top()); que2.pop(); } puts(""); puts(""); printf("采纳头文件\"functional\"内定义优先级:\n(priority_queue<int,vector<int>,greater<int>/less<int> >que;)\n"); printf("Queue 3:\n"); while(!que3.empty()){ printf("%3d",que3.top()); que3.pop(); } puts(""); printf("Queue 4:\n"); while(!que4.empty()){ printf("%3d",que4.top()); que4.pop(); } puts(""); puts(""); printf("采纳构造体自定义优先级形式二:\n(priority_queue<number>que)\n"); printf("Queue 5:\n"); while(!que5.empty()){ printf("%3d",que5.top()); que5.pop(); } puts(""); printf("Queue 6:\n"); while(!que6.empty()){ printf("%3d",que6.top()); que6.pop(); } puts(""); return 0;}/*运行后果 ：采纳默认优先关系:(priority_queue<int>que;)Queue 0:83 72 56 47 36 22 14 10 7 3采纳构造体自定义优先级形式一:(priority_queue<int,vector<int>,cmp>que;)Queue 1: 7 10 14 22 36 47 56 72 83 91Queue 2:83 72 56 47 36 22 14 10 7 3采纳头文件"functional"内定义优先级:(priority_queue<int,vector<int>,greater<int>/less<int> >que;)Queue 3: 7 10 14 22 36 47 56 72 83 91Queue 4:83 72 56 47 36 22 14 10 7 3采纳构造体自定义优先级形式二:(priority_queue<number>que)Queue 5: 7 10 14 22 36 47 56 72 83 91Queue 6:83 72 56 47 36 22 14 10 7 3*///priority_queue<Type,Container,Compare> // Type 为数据类型 // Container 为保留数据的容器, 必须是用数组实现的容器，比方 vector, deque 但不能用list。STL外面默认用的是 vector // Compare为元素比拟形式。. 比拟形式默认用 operator< , 所以如果你把前面俩个参数缺省的话，优先队列就是大顶堆，队头元素最大。 小利用
某元素有X和Y两个属性，按X对该元素排序，X相等时按Y排序。
#include<iostream>#include<queue>#include<cstdio>#include<stdlib.h>#include<string.h>using namespace std;struct Node{ int x; int y; Node( int a=0, int b=0 ): x(a),y(b) { }};struct cmp{ bool operator() ( Node a, Node b ){ if( a.x==b.x ) return a.y>b.y; return a.x>b.x; }};int main(){ priority_queue<Node, vector<Node>,cmp> q; for(int i=0; i<10; ++i) q.push( Node( rand(), rand() ) ); while( !q.empty() ){ cout << q.top().x <<" "<< q.top().y << endl; q.pop(); } getchar(); return 0;}