STl 优先队列 C++

c++中的STL 中的优先队列

参照网址：

https://www.cnblogs.com/xzxl/p/7266404.html 代码示例

https://www.cnblogs.com/zhouzhihao/p/10974594.html 优先队列

//date:2020.5.2
#include <bits/stdc++.h>
using namespace std;
//重载运算符
struct 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;//最小值优先
    }
};
struct 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;

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

    priority_queue<int,vector<int>,greater<int> >que3;
    priority_queue<int,vector<int>,less<int> >que4;

    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:
(priority_queue<int>que;)
");
    printf("Queue 0:
");
    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:
(priority_queue<int,vector<int>,cmp>que;)
");
    printf("Queue 1:
");
    while(!que1.empty())
    {
        printf("%3d",que1.top());
        que1.pop();
    }
    puts("");
    printf("Queue 2:
");
    while(!que2.empty())
    {
        printf("%3d",que2.top());
        que2.pop();
    }
    puts("");
    puts("");
    printf("采用头文件"functional"内定义优先级:
(priority_queue<int,vector<int>,greater<int>/less<int> >que;)
");
    printf("Queue 3:
");
    while(!que3.empty())
    {
        printf("%3d",que3.top());
        que3.pop();
    }
    puts("");
    printf("Queue 4:
");
    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:
(priority_queue<number>que)
");
    printf("Queue 5:
");
    while(!que5.empty())
    {
        printf("%3d",que5.top());
        que5.pop();
    }
    puts("");
    printf("Queue 6:
");
    while(!que6.empty())
    {
        printf("%3d",que6.top());
        que6.pop();
    }
    puts("");
    return 0;
}

输出结果

采用默认优先关系:
(priority_queue<int>que;)
Queue 0:
 91 83 72 56 47 36 22 14 10  7  3

采用结构体自定义优先级方式一:
(priority_queue<int,vector<int>,cmp>que;)
Queue 1:
  3  7 10 14 22 36 47 56 72 83 91
Queue 2:
 91 83 72 56 47 36 22 14 10  7  3

采用头文件"functional"内定义优先级:
(priority_queue<int,vector<int>,greater<int>/less<int> >que;)
Queue 3:
  3  7 10 14 22 36 47 56 72 83 91
Queue 4:
 91 83 72 56 47 36 22 14 10  7  3

采用结构体自定义优先级方式二:
(priority_queue<number>que)
Queue 5:
  3  7 10 14 22 36 47 56 72 83 91
Queue 6:
 91 83 72 56 47 36 22 14 10  7  3

　　

四种运算符重载的方法

struct node{
    int x;
    int y;
    friend bool operator<(const node a,const node b)
    {
        return a.x>b.x;
    }
};
priority_queue<node> Q;

struct node{
    int x;
    int y;
    bool operator<(const node &a) const
    {
        return x>a.x;
    }
};
priority_queue<node> Q;

struct node{
    int x;
    int y;
}point;
bool operator<(const node &a,const node &b)
{
    return a.x>b.x;
}
priority_queue<node> Q;

struct node{
    int x;
    int y;
};
struct cmp{
    bool operator()(node a,node b){
        return a.x>b.x;
    }
};
priority_queue<node,vector<node>,cmp> Q;