Language: C++

#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream>
#include <random>
#include<map>
#include <iomanip>
#include <time.h>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
#include <cassert>
#include<fstream>
#include <unordered_map>
#include <cstdlib>
using namespace std;
#define Ma_PI 3.141592653589793
#define eps 0.00000001
#define LONG_INF 3000000000000000000
#define GOLD 1.61803398874989484820458
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
#define seg_size 524288
int main() {
#define int long long
	string s;
	cin >> s;
	long long ans = 0;
	for (int tere = 0;tere < 2;++tere) {
		int back = -1;
		long long pre_ans = s.length();
		for (int i = 0;i < s.length();++i) {
			if (s[i] == '1') {
				if (back == -1) back = i;
			}else{
				if (back != -1) {
					pre_ans = min(pre_ans, max(max(back,(long long)s.length() - i),i - back));
				}
			}
		}
		if (back != -1) {
			pre_ans = min(pre_ans, max(back, s.length() - back));
		}
		ans = max(pre_ans, ans);
		for (int q = 0;q < s.length();++q) {
			if (s[q] == '1') s[q] = '0';
			else s[q] = '1';
		}
	}
	cout << ans << endl;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:53:51: error: no matching function for call to 'max(long long int&, long long unsigned int)'
   53 |                         pre_ans = min(pre_ans, max(back, s.length() - back));
      |                                                ~~~^~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 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:53:51: note:   deduced conflicting types for parameter 'const _Tp' ('long long int' and 'long long unsigned int')
   53 |                         pre_ans = min(pre_ans, max(back, s.length() - back));
      |                                                ~~~^~~~~~~~~~~~~~~~~~~~~~~~~
/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:53:51: note:   mismatched types 'std::initializer_list<_Tp>' and 'long long int'
   53 |                         pre_ans = min(pre_ans, max(back, s.length() - back));
      |                                                ~~~^~~~~~~~~~~~~~~~~~~~~~~~~