Question

PriorityQueue使用求助

Answer 1

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();

[cpp] view plain copy print?
#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;
}