Language: C++

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vint;
typedef pair<int,int> pint;
typedef vector<pint> vpint;
#define rep(i,n) for(int i=0;i<(n);i++)
#define REP(i,n) for(int i=n-1;i>=(0);i--)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
#define all(v) (v).begin(),(v).end()
#define eall(v) unique(all(v), v.end())
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define chmax(a, b) a = (((a)<(b)) ? (b) : (a))
#define chmin(a, b) a = (((a)>(b)) ? (b) : (a))
const int MOD = 1e9 + 7;
const int INF = 1e9;
const ll INFF = 1e18;

int main() {
	string s; cin >> s;
	int ans = 0;
	rep(i, s.size() - 1) {
		if (s[i] != s[i + 1]) {
			ans = chmax(ans, max(i, s.size() - i));
		}
	}
	printf("%d\n", ans);
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:28:45: error: no matching function for call to 'max(int&, std::__cxx11::basic_string<char>::size_type)'
   28 |                         ans = chmax(ans, max(i, s.size() - i));
      |                                          ~~~^~~~~~~~~~~~~~~~~
a.cc:17:32: note: in definition of macro 'chmax'
   17 | #define chmax(a, b) a = (((a)<(b)) ? (b) : (a))
      |                                ^
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:28:45: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'})
   28 |                         ans = chmax(ans, max(i, s.size() - i));
      |                                          ~~~^~~~~~~~~~~~~~~~~
a.cc:17:32: note: in definition of macro 'chmax'
   17 | #define chmax(a, b) a = (((a)<(b)) ? (b) : (a))
      |                                ^
/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:28:45: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   28 |                         ans = chmax(ans, max(i, s.size() - i));
      |                                          ~~~^~~~~~~~~~~~~~~~~
a.cc:17:32: note: in definition of macro 'chmax'
   17 | #define chmax(a, b) a = (((a)<(b)) ? (b) : (a))
      |                                ^
a.cc:28:45: error: no matching function for call to 'max(int&, std::__cxx11::basic_string<char>::size_type)'
   28 |                         ans = chmax(ans, max(i, s.size() - i));
      |                                          ~~~^~~~~~~~~~~~~~~~~
a.cc:17:39: note: in definition of macro 'chmax'
   17 | #define chmax(a, b) a = (((a)<(b)) ? (b) : (a))
      |                                       ^
/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:28:45: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'})
   28 |                         ans = chmax(ans, max(i, s.size() - i));
      |                                          ~~~^~~~~~~~~~~~~~~~~
a.cc:17:39: note: in definition of macro 'chmax'
   17 | #define chmax(a, b) a = (((a)<(b)) ? (b) : (a))
      |                                       ^
/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
/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:28:45: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   28 |                         ans = chmax(ans, max(i, s.size() - i));
      |                                          ~~~^~~~~~~~~~~~~~~~~
a.cc:17:39: note: in definition of macro 'chmax'
   17 | #define chmax(a, b) a = (((a)<(b)) ? (b) : (a))
      |                                       ^