Language: C++

#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <functional>
#include <set>
#include <ctime>
#include <random>
#include <chrono>
#include <cassert>
#include <tuple>
#include <utility>
using namespace std;

namespace {
  using Integer = long long; //__int128;
  template<class T, class S> istream& operator >> (istream& is, pair<T,S>& p){return is >> p.first >> p.second;}
  template<class T> istream& operator >> (istream& is, vector<T>& vec){for(T& val: vec) is >> val; return is;}
  template<class T> istream& operator ,  (istream& is, T& val){ return is >> val;}
  template<class T, class S> ostream& operator << (ostream& os, const pair<T,S>& p){return os << p.first << " " << p.second;}
  template<class T> ostream& operator << (ostream& os, const vector<T>& vec){for(size_t i=0; i<vec.size(); i++) os << vec[i] << (i==vec.size()-1?"":" "); return os;}
  template<class T> ostream& operator ,  (ostream& os, const T& val){ return os << " " << val;}

  template<class H> void print(const H& head){ cout << head; }
  template<class H, class ... T> void print(const H& head, const T& ... tail){ cout << head << " "; print(tail...); }
  template<class ... T> void println(const T& ... values){ print(values...); cout << endl; }

  template<class H> void eprint(const H& head){ cerr << head; }
  template<class H, class ... T> void eprint(const H& head, const T& ... tail){ cerr << head << " "; eprint(tail...); }
  template<class ... T> void eprintln(const T& ... values){ eprint(values...); cerr << endl; }

  class range{ Integer start_, end_, step_; public: struct range_iterator{ Integer val, step_; range_iterator(Integer v, Integer step) : val(v), step_(step) {} Integer operator * (){return val;} void operator ++ (){val += step_;} bool operator != (range_iterator& x){return step_ > 0 ? val < x.val : val > x.val;} }; range(Integer len) : start_(0), end_(len), step_(1) {} range(Integer start, Integer end) : start_(start), end_(end), step_(1) {} range(Integer start, Integer end, Integer step) : start_(start), end_(end), step_(step) {} range_iterator begin(){ return range_iterator(start_, step_); } range_iterator   end(){ return range_iterator(  end_, step_); } };

  inline string operator "" _s (const char* str, size_t size){ return move(string(str)); }
  constexpr Integer my_pow(Integer x, Integer k, Integer z=1){return k==0 ? z : k==1 ? z*x : (k&1) ? my_pow(x*x,k>>1,z*x) : my_pow(x*x,k>>1,z);}
  constexpr Integer my_pow_mod(Integer x, Integer k, Integer M, Integer z=1){return k==0 ? z%M : k==1 ? z*x%M : (k&1) ? my_pow_mod(x*x%M,k>>1,M,z*x%M) : my_pow_mod(x*x%M,k>>1,M,z);}
  constexpr unsigned long long operator "" _ten (unsigned long long value){ return my_pow(10,value); }

  inline int k_bit(Integer x, int k){return (x>>k)&1;} //0-indexed

  mt19937 mt(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count());

  template<class T> string join(const vector<T>& v, const string& sep){ stringstream ss; for(size_t i=0; i<v.size(); i++){ if(i>0) ss << sep; ss << v[i]; } return ss.str(); }

  inline string operator * (string s, int k){ string ret; while(k){ if(k&1) ret += s; s += s; k >>= 1; } return ret; }
}
constexpr long long mod = 9_ten + 7;


class starry_sky_tree{
public:
  static const int MAX_SIZE = 1 << 17; //segment tree のサイズ。 2^17 ≒ 1.3 * 10^5
  using Int = long long;
  Int segMin[2 * MAX_SIZE - 1], segAdd[2 * MAX_SIZE - 1];

  starry_sky_tree(){
    fill(segMin, segMin + 2*MAX_SIZE-1, 0);
    fill(segAdd, segAdd + 2*MAX_SIZE-1, 0);
  }

  //区間[a, b)に値xを加算する.
  void add(int a, int b, Int x, int k = 0, int l = 0, int r = MAX_SIZE)
  {
    if (r <= a || b <= l) return; //もし交差しない区間であれば終える.
    
    if (a <= l && r <= b){ //もし今みている区間[l, r)が[a, b)に完全に内包されていれば
      segAdd[k] += x;  //区間[l, r)にkを加算する.
      return;
    }
    
    add(a, b, x, k * 2 + 1, l, (l + r) / 2); //子の区間に(必要があれば)xを加算する.
    add(a, b, x, k * 2 + 2, (l + r) / 2, r); //〃

    //親の区間の最小値は, 子の区間の最小値 + 自分に一様に加算されている値 である.一様に加算される値は更新しなくて良い.
    segMin[k] = min(segMin[k * 2 + 1] + segAdd[k * 2 + 1], segMin[k * 2 + 2] + segAdd[k * 2 + 2]);
  }

  Int getMin(int a, int b, int k = 0, int l = 0, int r = MAX_SIZE)
  {
    if (r <= a || b <= l) return (LLONG_MAX);
    
    if (a <= l && r <= b) return (segMin[k] + segAdd[k]); //完全に内包されていれば,その区間の最小値を返す.
    
    Int left = getMin(a, b, k * 2 + 1, l, (l + r) / 2); //子の区間の最小値を求める.
    Int right = getMin(a, b, k * 2 + 2, (l + r) / 2, r); //子の区間の最小値を求める
    
    return (min(left, right) + segAdd[k]); //親の区間の最小値は, 子の区間の最小値 + 自分に一様に加算されている値 である (大切なので2回書きました!!)
    
  }
};

int main(){
  int n;
  long long e,t;
  cin >> n,e,t;

  //assert(n<=2000);

  vector<long long> x(n);
  cin >> x;
  x.push_back(e);
  x.push_back(1ll<<57);

  starry_sky_tree a, b;

  vector<long long> dp(n+1, 1ll<<57);
  dp[0] = 0;

  for(int i=0, j=0; i<n; i++){
    while(j<i && t < 2*(x[i] - x[j]) ){
      j++;
    }
    if(j) dp[i+1] = min(dp[i+1], a.getMin(0, j));
    dp[i+1] = min(dp[i+1], t+ b.getMin(j, i+1));

    a.add(0,i+1, 2*(x[i+1]-x[i]));
    b.add(i+1, i+2, dp[i+1]);
  }
  println(dp[n] + e);

  //eprintln(join(dp, " "));

  return 0;
}


Compiler output:
a.cc: In member function 'starry_sky_tree::Int starry_sky_tree::getMin(int, int, int, int, int)':
a.cc:85:35: error: 'LLONG_MAX' was not declared in this scope
   85 |     if (r <= a || b <= l) return (LLONG_MAX);
      |                                   ^~~~~~~~~
a.cc:18:1: note: 'LLONG_MAX' is defined in header '<climits>'; this is probably fixable by adding '#include <climits>'
   17 | #include <utility>
  +++ |+#include <climits>
   18 | using namespace std;