Language: C++

#include <iostream>
#include <string>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <vector>
#include <cmath>
#include <cstdlib>
#include <queue>
#include <stack>
#include <iomanip>

using namespace std;

#define REP(i, n) for(ll i = 0;i < n;i++)
#define REPR(i, n) for(ll i = n;i >= 0;i--)
#define FOR(i, m, n) for(ll i = m;i < n;i++)
#define FORR(i, m, n) for(ll i = m;i >= n;i--)
#define REPO(i, n) for(ll i = 1;i <= n;i++)
#define ll long long
#define INF (ll)1 << 60
#define MINF (-1 * INF)
#define ALL(n) n.begin(),n.end()
#define MOD 1000000007
#define P pair<ll, ll>


string s;
bool t0, t1;
ll ans = 0;
int main() {
	cin >> s;
	REP(i, s.size()) {
		if (s[i] == '0')t0 = true;
		if (s[i] == '1')t1 = true;
	}
	if (!t0 or !t1) {
		cout << s.size() << endl;
		return 0;
	}
	REP(i, s.size() - 1) {
		if (s[i] != s[i + 1]) {
			ll now = 2, to = i;
			REPR(j, i - 1) {
				if (s[i] != s[j])break;
				 now++;
			}
			FOR(j, i + 2, s.size()) {
				if (s[i + 1] != s[j]) {
					to = j - 1;
					break;
				}
				now++;
			}
			ans = max(ans, min(max(i + 1, s.size() - i - 1), now));
			i = to;
		}
	}
	cout << ans << endl;
}




Compiler output:
a.cc: In function 'int main()':
a.cc:56:47: error: no matching function for call to 'max(long long int, long long unsigned int)'
   56 |                         ans = max(ans, min(max(i + 1, s.size() - i - 1), now));
      |                                            ~~~^~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/string:51,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 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:56:47: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'long long unsigned int')
   56 |                         ans = max(ans, min(max(i + 1, s.size() - i - 1), now));
      |                                            ~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/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,
                 from a.cc:4:
/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:56:47: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   56 |                         ans = max(ans, min(max(i + 1, s.size() - i - 1), now));
      |                                            ~~~^~~~~~~~~~~~~~~~~~~~~~~~~