STL 优先队列的 优先级

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;//最大值优先
}
};
struct node1
{
int u;
bool operator < (const node1 &a) const
{
return u>a.u;//最小值优先
}
};
struct node2
{
int u;
bool operator < (const node2 &a) const
{
return u<a.u;//最大值优先
}
};

priority_queue<int>q1;//采用默认优先级构造队列
priority_queue<int,vector<int>,cmp1>q2;//最小值优先
priority_queue<int,vector<int>,cmp2>q3;//最大值优先
priority_queue<int,vector<int>,greater<int> >q4;//注意“>>”会被认为错误，
//这是右移运算符，所以这里用空格号隔开,最小值优先
priority_queue<int,vector<int>,less<int> >q5;//最大值优先
priority_queue<node1>q6;  //自定义优先级
priority_queue<node2>q7;