comparison class usage in priority_queue

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There is a way to use customized comparison function in C++ priority_queue. Instead of reloading the ‘less than’ operator, one can also write a compare class in which the ‘()’ operator is reloaded when defining. Here is an example:

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#include<bits/stdc++.h>
using namespace std;

class pts {
	public:
		int x,y;
};

class comp {
	public:
		bool operator() (pts a, pts b){
			return a.x < b.x;
		}
};

int main() {
	priority_queue<pts, vector<pts>, comp> s;
	return 0;
}