foo.cc: In function 'void search_nlogn(ll)':
foo.cc:14:17: error: 'lower_bound' was not declared in this scope; did you mean 'std::lower_bound'?
   14 |         int j = lower_bound(sum, sum + n, y) - sum;
      |                 ^~~~~~~~~~~
      |                 std::lower_bound
In file included from /usr/include/c++/9/algorithm:62,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:65,
                 from foo.cc:1:
/usr/include/c++/9/bits/stl_algo.h:2028:5: note: 'std::lower_bound' declared here
 2028 |     lower_bound(_ForwardIterator __first, _ForwardIterator __last,
      |     ^~~~~~~~~~~
foo.cc:16:13: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   16 |             cout << i + 1 << " " << j << endl;
      |             ^~~~
      |             std::cout
In file included from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:75,
                 from foo.cc:1:
/usr/include/c++/9/iostream:61:18: note: 'std::cout' declared here
   61 |   extern ostream cout;  /// Linked to standard output
      |                  ^~~~
foo.cc:16:42: error: 'endl' was not declared in this scope; did you mean 'std::endl'?
   16 |             cout << i + 1 << " " << j << endl;
      |                                          ^~~~
      |                                          std::endl
In file included from /usr/include/c++/9/istream:39,
                 from /usr/include/c++/9/sstream:38,
                 from /usr/include/c++/9/complex:45,
                 from /usr/include/c++/9/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:54,
                 from foo.cc:1:
/usr/include/c++/9/ostream:599:5: note: 'std::endl' declared here
  599 |     endl(basic_ostream<_CharT, _Traits>& __os)
      |     ^~~~
foo.cc: In function 'int main()':
foo.cc:22:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
   22 |     cin>>M;
      |     ^~~
      |     std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:75,
                 from foo.cc:1:
/usr/include/c++/9/iostream:60:18: note: 'std::cin' declared here
   60 |   extern istream cin;  /// Linked to standard input
      |                  ^~~
foo.cc:24:5: error: 'search' was not declared in this scope; did you mean 'std::search'?
   24 |     search(M);
      |     ^~~~~~
      |     std::search
In file included from /usr/include/c++/9/algorithm:62,
                 from /usr/include/x86_64-linux-gnu/c++/9/bits/stdc++.h:65,
                 from foo.cc:1:
/usr/include/c++/9/bits/stl_algo.h:4216:5: note: 'std::search' declared here
 4216 |     search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
      |     ^~~~~~
foo.cc:23:8: warning: unused variable 'a' [-Wunused-variable]
   23 |     ll a,b;
      |        ^
foo.cc:23:10: warning: unused variable 'b' [-Wunused-variable]
   23 |     ll a,b;
      |          ^

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