priority_queue使用方法

从大到小：

priority_queue: 默认
9 6 5 3 2

由小到大：
priority_queue<int, vector<int>, greater<int> >
2 3 5 6 9;

由大到小：
struct node
{
    friend bool operator< (node n1, node n2)
    {
        return n1.priority < n2.priority;
    }
    int priority;
    int value;
};

9 6 5 3 2


priority_queue<int> que;
que.push();
que.top();

que.pop();

#include<iostream>
#include<functional>
#include<queue>
#include<vector>
using namespace std;


struct cmp1
{
	bool operator () (int &a, int &b)
	{
		return a > b ;              // 从小到大排序，值 小的 优先级别高
	}
};

struct cmp2
{
	bool operator () (int &a, int &b)
	{
		return a < b;             // 从大到小
	}
};

struct number1
{
	int x;
	bool operator < (const number1 &a)const 
	{
		return x > a.x;         // 从小到大  ，x 小的 优先级别高
	}
};

struct number2
{
	int x;
	bool operator < (const number2 &a)const
	{
		return x < a.x;            // 从大到小  ，x 大的优先级别高
	}
};

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;  // 采用默认优先级构造队列  从大到小。 

        priority_queue<int, vector<int>, cmp1 >que1;
	priority_queue<int, vector<int>, cmp2 >que2;

	priority_queue<int, vector<int>, greater<int> > que3;  //functional 头文件自带的 
	priority_queue<int, vector<int>, less<int> > que4;      //functional 头文件自带的 

	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("采用默认优先关系:\n(priority_queue<int>que;)\n");
	printf("Queue 0:\n");
        while(!que.empty())
	{
		printf("%3d",que.top());
		que.pop();
	}
	puts("");
	puts("");

    printf("采用结构体自定义优先级方式一:\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("采用头文件\"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("采用结构体自定义优先级方式二:\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();
	}

	system("pause");
	return 0;
}