struct road
{
    int x,y,count;//横纵坐标和花费的费用
    /*friend bool operator<(road a,road b)//定义结构体的优先级比较方式        //这种形式是将比较运算符内置
    {
        return a.count>b.count;
    }*/
}st,tp;


如果将比较运算符外置，该怎么写？我自己想的不知道对不对 请给位指教。。
struct cmp                                                               
{
     bool operator () (road a, road b) // 重载括号
    {
        return a.count >b.count; // 相当于less，大顶堆
    }
};
priority_queue<road，vector<road>,cmp> q;

struct road
{
    int x,y,count;
    friend bool operator<(road a,road b)//定义结构体的优先级比较方，这种形式是将比较运算符内置
    {
        return a.count>b.count;
    }
}st,tp;


下面这种是将比较运算符外置
struct road
{
    int x,y,count;
}st,tp;

struct cmp                                                               
{
     bool operator () (road a, road b) // 重载括号
    {
        return a.count >b.count; // 相当于less，大顶堆
    }
};
priority_queue<road，vector<road>,cmp> q