优先队列priority_queue的比较函数

priority_queue<int, vector<int>, less<int> > q;//等价于默认，从大到小排
//greater<int> 从小到大排

bool operator < (const node &a, const node &b) 
 {
     return a.value < b.value; // 按照value从大到小排列
 } 
priority_queue<node>q;

struct cmp{

    bool operator ()(const node &a, const node &b)
    {
        return a.value>b.value;// 按照value从小到大排列
    }
};
priority_queue<node, vector<node>, cmp>q;

struct node{
    int value;
    friend bool operator<(const node &a,const node &b){
        return a.value<b.value;  //按value从大到小排列
    }
};
priority_queue<node>q;