how to declare comparator for set of pair
#include <iostream>
#include <set>
using namespace std;
bool comparePairs(const pair<int, int>& p1, const pair<int, int>& p2) {
if (p1.first != p2.first) {
return p1.first < p2.first;
}
return p1.second < p2.second;
}
int main() {
set<pair<int, int>, decltype(&comparePairs)> pairSet(&comparePairs);
pairSet.insert({1, 2});
pairSet.insert({2, 1});
pairSet.insert({1, 3});
for (const auto& p : pairSet) {
cout << "(" << p.first << ", " << p.second << ") ";
}
cout << endl;
return 0;
}