Language: C++

/*Function Template*/
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
const int MAX = 510000;
const int MOD = 1000000007;
#define rep(i, n) for(ll i = 0; i < (n); i++)
#define ALL(a)  (a).begin(),(a).end()
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll fac[MAX], finv[MAX], inv[MAX];

// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (ll i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }

}
ll Len(ll n) {
  ll s=0;
  while(n!=0) s++, n/=10;
  return s;
}


ll Sint(ll n) {
  ll m=0,s=0,a=n;
  while(a!=0) s++, a/=10;
  for(ll i=s-1;i>=0;i--) m+=n/((ll)pow(10,i))-(n/((ll)pow(10,i+1)))*10;
  return m;
}


ll Svec(vector<ll> v){
  ll n=0;
  for(ll i=0;i<v.size();i++) n+=v[i];
  return n;
}


ll GCD(ll a,ll b){
  ll r,tmp;
/*自然数 a > b を確認・入替*/
  if(a<b){
    tmp=a,a=b,b=tmp;
  }
/*ユークリッドの互除法*/
  r=a%b;
  while(r!=0){
    a=b,b=r,r=a%b;
  }
  return b;
}


ll LCM(ll a,ll b){
  ll c=a,d=b,r,tmp;
/*自然数 a > b を確認・入替*/
  if(a<b){
    tmp=a,a=b,b=tmp;
  }
/*ユークリッドの互除法*/
  r=a%b;
  while(r!=0){
    a=b,b=r,r=a%b;
  }
  return c/b*d;
}


ll Factorial(ll n){
  ll m=1;
  while(n>=1) m*=n,n--;
  return m;
}

vector<pair<char,ll>> runlength(string s,vector<pair<char,ll>> p){
  ll x=1;
  if(s.size()==1){
    p.push_back(pair<char,ll>(s[0],1));
    return p;
  }
  for(ll i=0;i<s.size()-1;i++){
    if(s[i]==s[i+1]){
      x++;
      if(i==s.size()-2){
        p.push_back(pair<char,ll>(s[i],x));
      }
    }else{
      p.push_back(pair<char,ll>(s[i],x));
      x=1;
      if(i==s.size()-2){
        p.push_back(pair<char,ll>(s[s.size()-1],x));
      }
    }
  }
  return p;
}


ll COM(ll n,ll k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

const int MAX_N=100010;
vector<bool> sieve_of_eratosthenes(){
  vector<bool> isPrime(MAX_N+1,true);
  for(int i=2;i<=MAX_N;i++){
    if(isPrime[i]){
      for(int j=2*i;j<=MAX_N;j+=i){
        isPrime[j]=false;
      }
    }
  }
  return isPrime;
}







/*↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓*/
int main() {
  IOS;
  ll n,k;
  cin>>n>>k;
  string s;
  cin>>s;
  vector<ll> nums;
  if(s[0]=='0') nums.push_back(0);
  for(ll i=0;i<s.size();){
    ll j=i;
    while(j<s.size() && s[i]==s[j]) j++;
    nums.push_back(j-i);
    i=j;
  }
  if(s.back()=='0') nums.push_back(0);
  vector<ll> sums(nums.size(),0);
  rep(i,nums.size()) sums[i+1]=sums[i]+nums[i];
  int res = 0;
    for (int left = 0; left < sums.size(); left += 2) {
        int right = left + K*2+1;
        if (right >= sums.size()) right = (ll)sums.size() - 1;
        res = max(res, sums[right] - sums[left]);
    }
    cout << res << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:151:28: error: 'K' was not declared in this scope
  151 |         int right = left + K*2+1;
      |                            ^
a.cc:153:18: error: no matching function for call to 'max(int&, __gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type)'
  153 |         res = max(res, sums[right] - sums[left]);
      |               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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:2:
/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:153:18: note:   deduced conflicting types for parameter 'const _Tp' ('int' and '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'})
  153 |         res = max(res, sums[right] - sums[left]);
      |               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/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:153:18: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
  153 |         res = max(res, sums[right] - sums[left]);
      |               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~