mecho.cpp: In function 'int main()':
mecho.cpp:66:17: error: no matching function for call to 'std::queue<int>::push(std::pair<int, int>&)'
66 | Q.push(begin);
| ^
In file included from /usr/include/c++/10/queue:64,
from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:86,
from mecho.cpp:1:
/usr/include/c++/10/bits/stl_queue.h:265:7: note: candidate: 'void std::queue<_Tp, _Sequence>::push(const value_type&) [with _Tp = int; _Sequence = std::deque<int, std::allocator<int> >; std::queue<_Tp, _Sequence>::value_type = int]'
265 | push(const value_type& __x)
| ^~~~
/usr/include/c++/10/bits/stl_queue.h:265:30: note: no known conversion for argument 1 from 'std::pair<int, int>' to 'const value_type&' {aka 'const int&'}
265 | push(const value_type& __x)
| ~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/10/bits/stl_queue.h:270:7: note: candidate: 'void std::queue<_Tp, _Sequence>::push(std::queue<_Tp, _Sequence>::value_type&&) [with _Tp = int; _Sequence = std::deque<int, std::allocator<int> >; std::queue<_Tp, _Sequence>::value_type = int]'
270 | push(value_type&& __x)
| ^~~~
/usr/include/c++/10/bits/stl_queue.h:270:25: note: no known conversion for argument 1 from 'std::pair<int, int>' to 'std::queue<int>::value_type&&' {aka 'int&&'}
270 | push(value_type&& __x)
| ~~~~~~~~~~~~~^~~