Structure & Priority Queue Custom Sorting

#include<bits/stdc++.h>  
using namespace std;  
typedef long long LL;  
struct node  
{  
    LL d;//Storage distance   
    int u;//The label of the point 	
    bool operator < ( const node& b) const// & means a reference,
	{
		return d > bd; // When defining a priority queue, the > here represents the order of entering a finite queue,
// That is, big first, so the order is small first  
	}
};
// < is an overloaded operator, that is, if there are two structures a, b must be a<b when comparing if the result is true, it means ad > bd; if it is false, it means ad < bd