Language: C++

#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < n; ++i)
#define rrep(i, n) for(int i = n-1; i >= 0; --i)
#define fi first
#define se second
using namespace std;
using lint = long long;
using uint = unsigned int;
using ulint = unsigned long long;
using ldouble = long double;
using pii = pair<int, int>;
using pli = pair<lint, lint>;
using pdd = pair<double, double>;
using pld = pair<ldouble, ldouble>;
using v1i = vector<int>;
using v1li = vector<lint>;
using v2i = vector<vector<int>>;
using v2li = vector<vector<lint>>;
using v3i = vector<vector<vector<int>>>;
using v3li = vector<vector<vector<lint>>>;
using v1b = vector<bool>;
using v2b = vector<vector<bool>>;
using v3b = vector<vector<vector<bool>>>;
using v1c = vector<char>;
using v2c = vector<vector<char>>;
using v3c = vector<vector<vector<char>>>;
constexpr lint mod1 = 1e9+7;
constexpr lint mod2 = 998244353;

int main() {
  int n, k, t = 0, u = 0, a = 0;
  scanf("%d %d", &n, &k);
  char s[n];
  scanf("%s", s);
  v1i p;
  rep(i, n+1){
    if(i == n){
      if(s[i-1] == '1') p.push_back(u);
      else{
        p.push_back(t);
        p.push_back(0);
      }
      break;
    }
    if(s[i] == '1'){
      if(t > 0 || i == 0) p.push_back(t);
      t = 0;
      ++u;
    }
    else{
      if(u > 0) p.push_back(u);
      u = 0;
      ++t;
    }
  }
  vector<pii> v; t = 0; v.push_back({0, 0});
  rep(i, p.size()/2){
    v.push_back({t+p[i*2], t+p[i*2]+p[i*2+1]});
    t += p[i*2]+p[i*2+1];
  }
  k = min(k, v.size()-1);
  rep(i, v.size()-k) a = max(a, v[k+i].se-v[i].fi);
  printf("%d\n", a);
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:61:10: error: no matching function for call to 'min(int&, std::vector<std::pair<int, int> >::size_type)'
   61 |   k = min(k, v.size()-1);
      |       ~~~^~~~~~~~~~~~~~~
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:233:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::min(const _Tp&, const _Tp&)'
  233 |     min(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:233:5: note:   template argument deduction/substitution failed:
a.cc:61:10: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'})
   61 |   k = min(k, v.size()-1);
      |       ~~~^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:281:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::min(const _Tp&, const _Tp&, _Compare)'
  281 |     min(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:281:5: 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:5686:5: note: candidate: 'template<class _Tp> constexpr _Tp std::min(initializer_list<_Tp>)'
 5686 |     min(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5686:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5696:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::min(initializer_list<_Tp>, _Compare)'
 5696 |     min(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5696:5: note:   template argument deduction/substitution failed:
a.cc:61:10: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   61 |   k = min(k, v.size()-1);
      |       ~~~^~~~~~~~~~~~~~~