Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long ;
using P = pair<ll, ll>;
using Vec = vector<ll>;
#define FOR(i, m, n) for(ll (i) = (m); (i) < (n); (i)++)
#define FORN(i, m, n) for(ll (i) = (m); (i) <= (n); (i)++)
#define FORR(i, m, n) for(ll (i) = (m); (i) >= (n); (i)--)
#define rep(i, n) FOR(i, 0, n)
#define repn(i, n) FORN(i, 1, n)
#define repr(i, n) FORR(i, n, 0)
#define repnr(i, n) FORR(i, n, 1)
#define co(n) cout << (n) << endl
#define cosp(n) cout << (n) << ' '
#define setp(n) cout << fixed << setprecision(n);
#define all(s) (s).begin(), (s).end()
#define pb push_back
#define mp make_pair
#define fs first
#define sc second

const ll INF = 1e9+1;
const ll LINF = 1e18+1;
const ll MOD = 1e9+7;
//const ll MOD = 998244353;
const double PI = acos(-1);
const double EPS = 1e-9;

int main(void){
	ll a, b, c, d;
	cin a >> b >> c >> d;
	ll ans = min(b, d)-max(a, c);
	co(max(ans, 0));

	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:31:12: error: expected ';' before 'a'
   31 |         cin a >> b >> c >> d;
      |            ^~
      |            ;
a.cc:33:15: error: no matching function for call to 'max(ll&, int)'
   33 |         co(max(ans, 0));
      |            ~~~^~~~~~~~
a.cc:13:24: note: in definition of macro 'co'
   13 | #define co(n) cout << (n) << endl
      |                        ^
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:33:15: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'int')
   33 |         co(max(ans, 0));
      |            ~~~^~~~~~~~
a.cc:13:24: note: in definition of macro 'co'
   13 | #define co(n) cout << (n) << endl
      |                        ^
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:33:15: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   33 |         co(max(ans, 0));
      |            ~~~^~~~~~~~
a.cc:13:24: note: in definition of macro 'co'
   13 | #define co(n) cout << (n) << endl
      |                        ^