Language: C++

#include "bits/stdc++.h"

using namespace std;

#define ll  long long
#define vi  vector<int>
#define pi  pair<int,int>
#define mp  make_pair
#define pb  push_back
#define MOD 1e9 + 7
#define PAI  3.1415
#define all(x) (x).begin(),(x).end()
#define chmax(x,y) x = max(x,y)
#define chmin(x,y) x = min(x,y)
#define pr(x) cout << x << endl
#define Endl endl
#define rep(i,n) for(int i = 0 ; i < n; i++)

const int dx[4] = {1,0,-1,0};
const int dy[4] = {0,1,0,-1};
const int inf = 99999999;
const ll linf = 1LL << 62;

ll gcd(ll a,ll b){
  if(a < b)swap(a , b);
  if(a % b == 0) return b;
  else gcd(b, a%b);
}

ll lcm(ll a,ll b){
  if(a < b)swap(a , b);
  return (a/gcd(a , b))*b;
}

  ll n,c;
  vector<pair<ll,ll> > v(100010);
  vector<ll> Asum(100010,0);
  vector<ll> Bsum(100010,0);
  vector<ll> Amax(100010,0);
  vector<ll> Amax_rep(100010,0);
  ll ans =0;

void solve(int pos){

  Asum[pos] = Asum[pos - 1] + v[pos].second;
  Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;

 }

int main(){

  cin >> n >>c;
  rep(i,n){
    ll a,b;
    cin >> a >> b;
    v[i + 1] = mp(a,b);
  }

  v[n+1]= mp(c,0);

  rep(i,n)solve(i + 1);

  rep(i,n){ // compute on A of rep and nonrep
    Amax[i + 1] = max(Amax[i], Asum[i + 1] - v[i + 1].first);
    Amax_rep[i + 1] = max(Amax_rep[i], Asum[i + 1] - 2*v[i + 1].first);
  }

  rep(i,n + 1){
    int pos = n - i + 1;
    ll ans1 = Amax[pos - 1] + Bsum[pos] - 2*(c - v[pos].first); //A nonrep and B rep
    chmax(ans,ans1);
    ll ans2 = Amax_rep[pos - 1] + Bsum[pos] - (c - v[pos].first); // A rep and B nonrep
    chmax(ans,ans2);
  }

  pr(ans);

  return 0;
}


Compiler output:
a.cc: In function 'void solve(int)':
a.cc:46:56: error: expected ']' before ')' token
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
      |                                                        ]
a.cc:46:41: error: no match for 'operator+' (operand types are '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'} and '__gnu_cxx::__alloc_traits<std::allocator<std::pair<long long int, long long int> >, std::pair<long long int, long long int> >::value_type' {aka 'std::pair<long long int, long long int>'})
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
In file included from /usr/include/c++/14/bits/stl_algobase.h:67,
                 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_iterator.h:627:5: note: candidate: 'template<class _Iterator> constexpr std::reverse_iterator<_Iterator> std::operator+(typename reverse_iterator<_Iterator>::difference_type, const reverse_iterator<_Iterator>&)'
  627 |     operator+(typename reverse_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:627:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::pair<long long int, long long int> >, std::pair<long long int, long long int> >::value_type' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note: candidate: 'template<class _Iterator> constexpr std::move_iterator<_IteratorL> std::operator+(typename move_iterator<_IteratorL>::difference_type, const move_iterator<_IteratorL>&)'
 1798 |     operator+(typename move_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1798:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::pair<long long int, long long int> >, std::pair<long long int, long long int> >::value_type' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::move_iterator<_IteratorL>'
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
In file included from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52:
/usr/include/c++/14/bits/basic_string.h:3598:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3598 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3598:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'}
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/basic_string.h:3616:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3616 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3616:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   mismatched types 'const _CharT*' and 'long long int'
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/basic_string.h:3635:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3635 |     operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3635:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   '__gnu_cxx::__alloc_traits<std::allocator<std::pair<long long int, long long int> >, std::pair<long long int, long long int> >::value_type' {aka 'std::pair<long long int, long long int>'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/basic_string.h:3652:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3652 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3652:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'}
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/basic_string.h:3670:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, _CharT)'
 3670 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3670:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'}
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/basic_string.h:3682:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3682 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3682:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'}
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/basic_string.h:3689:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3689 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3689:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'}
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/basic_string.h:3696:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3696 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3696:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'}
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/basic_string.h:3719:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, __cxx11::basic_string<_CharT, _Traits, _Allocator>&&)'
 3719 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3719:5: note:   template argument deduction/substitution failed:
a.cc:46:56: note:   mismatched types 'const _CharT*' and 'long long int'
   46 |   Bsum[n - pos + 1] = Bsum[n - pos + 2] + v[n - pos + 1)].second;
      |                                                        ^
/usr/include/c++/14/bits/basic_string.h:3726:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std: