Can you explain the output

#1

What will be the output of following C++ code?

#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pi;
struct Compare
{
bool operator()(pi const & a, pi const & b)
{
if(a.second < b.second)
{
return true;
}
else if(a.second > b.second)
{
return false;
}
else
{
if(a.first > b.first)
{
return true;
}
return false;
}
}
};
int main()
{
priority_queue<pi , vector, Compare>q;
q.push({1, 5});
q.push({5, 15});
q.push({7, 15});
q.push({10, 2});
q.push({1, 10});
cout<<q.top().first<<" "<<q.top().second<<endl;
return 0;
}

My answer is 7 15
How the comparison works in each call?
#2

It must be
5 15

Because:
if(a.second < b.second)
{
return true;
}
Due to this a max heap will be formed based on second element.
When second element is same as in ({5, 15}) and ({7, 15}), the else part would be executed
Since in else part:
if(a.first > b.first)
{
return true;
}
So a min heap based on first element would be formed.
So…at the end the top of the heap would have {5, 15}

#3

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