【c++】priority_queue自定义小根堆

struct ListNode {
    
    
    int val;
    ListNode *next;
    ListNode() : val(0), next(nullptr) {
    
    }
    ListNode(int x) : val(x), next(nullptr) {
    
    }
    ListNode(int x, ListNode *next) : val(x), next(next) {
    
    }
};
struct cmp{
    
    
    bool operator()(ListNode *a, ListNode *b){
    
    
    return a->val > b->val; //是> 而不是<
    }
};
int main(){
    
    
	priority_queue<ListNode *, vector<ListNode *>, cmp> q;//自定义小根堆
	priority_queue<int> q;//默认大根堆
	priority_queue<int, vector<int>, greater<int>> q;//小根堆
    return 0;
}