Problem p02603 (C++) — buggy submission, verdict: Runtime Error

// Marcin Knapik
#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

using namespace std;

// #include <ext/pb_ds/assoc_container.hpp> // order_of_key
// #include <ext/pb_ds/tree_policy.hpp> // find by order
// using namespace __gnu_pbds;
// #define ordered_set tree< int , null_type,less< int >,
// rb_tree_tag,tree_order_statistics_node_update>

// const ll MAX_LL = 0xFFFFFFFFFFFFFFFF;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define losuj(a, b) uniform_int_distribution<ll>(a, b)(rng)

typedef long double ld;
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
#define pll pair<long long, long long>
#define vpll vector<pll>
#define ull unsigned long long

#define sz(a) (int)(a).size()
#define pb push_back
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define FOR(i, a) for (int i = 0; i < (a); i++)
#define f first
#define s second

template <class T> inline bool setmin(T &a, T b) {
  if (a > b)
    return a = b, 1;
  return 0;
}
template <class T> inline bool setmax(T &a, T b) {
  if (a < b)
    return a = b, 1;
  return 0;
}

template <class T> inline T fast(T a, T b, T mod) {
  ll res = 1;
  while (b) {
    if (b & 1)
      res = (res * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return res;
}
template <class T> istream &operator>>(istream &os, vector<T> &container) {
  for (auto &u : container)
    os >> u;
  return os;
}
template <class T>
ostream &operator<<(ostream &os, const vector<T> &container) {
  for (auto &u : container)
    os << u << " ";
  return os;
}
template <class T> inline T gcd(T a, T b) {
  while (b)
    swap(a %= b, b);
  return abs(a);
}

const ll INF = 1e9 + 7;
const ll mod = 998244353;
const ll BIG_INF = 1e18 + 7;
const ll N = 1e6 + 7;
const ll T = 1 << 20;
const ld inf = 1e18;
// NOTE:
// This code contains various bug fixes compared to the original version from
// indy256
// (github.com/indy256/codelibrary/blob/master/cpp/numbertheory/bigint-full.cpp),
// including:
// - Fix overflow bug in mul_karatsuba.
// - Fix overflow bug in fft.
// - Fix bug in initialization from long long.
// - Optimized operators + - *.
//
// Tested:
// - https://www.e-olymp.com/en/problems/266: Comparison
// - https://www.e-olymp.com/en/problems/267: Subtraction
// - https://www.e-olymp.com/en/problems/271: Multiplication
// - https://www.e-olymp.com/en/problems/272: Multiplication
// - https://www.e-olymp.com/en/problems/313: Addition
// - https://www.e-olymp.com/en/problems/314: Addition/Subtraction
// - https://www.e-olymp.com/en/problems/317: Multiplication (simple / karatsuba
// / fft)
// - https://www.e-olymp.com/en/problems/1327: Multiplication
// - https://www.e-olymp.com/en/problems/1328
// - VOJ BIGNUM: Addition, Subtraction, Multiplication.
// - SGU 111: sqrt
// - SGU 193
// - SPOJ MUL, VFMUL: Multiplication.
// - SPOJ FDIV, VFDIV: Division.

const int BASE_DIGITS = 9;
const int BASE = 1000000000;

struct BigInt {
  int sign;
  vector<int> a;

  // -------------------- Constructors --------------------
  // Default constructor.
  BigInt() : sign(1) {}

  // Constructor from long long.
  BigInt(long long v) { *this = v; }
  BigInt &operator=(long long v) {
    sign = 1;
    if (v < 0) {
      sign = -1;
      v = -v;
    }
    a.clear();
    for (; v > 0; v = v / BASE)
      a.push_back(v % BASE);
    return *this;
  }

  // Initialize from string.
  BigInt(const string &s) { read(s); }

  // -------------------- Input / Output --------------------
  void read(const string &s) {
    sign = 1;
    a.clear();
    int pos = 0;
    while (pos < (int)s.size() && (s[pos] == '-' || s[pos] == '+')) {
      if (s[pos] == '-')
        sign = -sign;
      ++pos;
    }
    for (int i = s.size() - 1; i >= pos; i -= BASE_DIGITS) {
      int x = 0;
      for (int j = max(pos, i - BASE_DIGITS + 1); j <= i; j++)
        x = x * 10 + s[j] - '0';
      a.push_back(x);
    }
    trim();
  }
  friend istream &operator>>(istream &stream, BigInt &v) {
    string s;
    stream >> s;
    v.read(s);
    return stream;
  }

  friend ostream &operator<<(ostream &stream, const BigInt &v) {
    if (v.sign == -1 && !v.isZero())
      stream << '-';
    stream << (v.a.empty() ? 0 : v.a.back());
    for (int i = (int)v.a.size() - 2; i >= 0; --i)
      stream << setw(BASE_DIGITS) << setfill('0') << v.a[i];
    return stream;
  }

  // -------------------- Comparison --------------------
  bool operator<(const BigInt &v) const {
    if (sign != v.sign)
      return sign < v.sign;
    if (a.size() != v.a.size())
      return a.size() * sign < v.a.size() * v.sign;
    for (int i = ((int)a.size()) - 1; i >= 0; i--)
      if (a[i] != v.a[i])
        return a[i] * sign < v.a[i] * sign;
    return false;
  }

  bool operator>(const BigInt &v) const { return v < *this; }
  bool operator<=(const BigInt &v) const { return !(v < *this); }
  bool operator>=(const BigInt &v) const { return !(*this < v); }
  bool operator==(const BigInt &v) const {
    return !(*this < v) && !(v < *this);
  }
  bool operator!=(const BigInt &v) const { return *this < v || v < *this; }

  // Returns:
  // 0 if |x| == |y|
  // -1 if |x| < |y|
  // 1 if |x| > |y|
  friend int __compare_abs(const BigInt &x, const BigInt &y) {
    if (x.a.size() != y.a.size()) {
      return x.a.size() < y.a.size() ? -1 : 1;
    }

    for (int i = ((int)x.a.size()) - 1; i >= 0; --i) {
      if (x.a[i] != y.a[i]) {
        return x.a[i] < y.a[i] ? -1 : 1;
      }
    }
    return 0;
  }

  // -------------------- Unary operator - and operators +- --------------------
  BigInt operator-() const {
    BigInt res = *this;
    if (isZero())
      return res;

    res.sign = -sign;
    return res;
  }

  // Note: sign ignored.
  void __internal_add(const BigInt &v) {
    if (a.size() < v.a.size()) {
      a.resize(v.a.size(), 0);
    }
    for (int i = 0, carry = 0; i < (int)max(a.size(), v.a.size()) || carry;
         ++i) {
      if (i == (int)a.size())
        a.push_back(0);

      a[i] += carry + (i < (int)v.a.size() ? v.a[i] : 0);
      carry = a[i] >= BASE;
      if (carry)
        a[i] -= BASE;
    }
  }

  // Note: sign ignored.
  void __internal_sub(const BigInt &v) {
    for (int i = 0, carry = 0; i < (int)v.a.size() || carry; ++i) {
      a[i] -= carry + (i < (int)v.a.size() ? v.a[i] : 0);
      carry = a[i] < 0;
      if (carry)
        a[i] += BASE;
    }
    this->trim();
  }

  BigInt operator+=(const BigInt &v) {
    if (sign == v.sign) {
      __internal_add(v);
    } else {
      if (__compare_abs(*this, v) >= 0) {
        __internal_sub(v);
      } else {
        BigInt vv = v;
        swap(*this, vv);
        __internal_sub(vv);
      }
    }
    return *this;
  }

  BigInt operator-=(const BigInt &v) {
    if (sign == v.sign) {
      if (__compare_abs(*this, v) >= 0) {
        __internal_sub(v);
      } else {
        BigInt vv = v;
        swap(*this, vv);
        __internal_sub(vv);
        this->sign = -this->sign;
      }
    } else {
      __internal_add(v);
    }
    return *this;
  }

  // Optimize operators + and - according to
  // https://stackoverflow.com/questions/13166079/move-semantics-and-pass-by-rvalue-reference-in-overloaded-arithmetic
  template <typename L, typename R>
  typename std::enable_if<std::is_convertible<L, BigInt>::value &&
                              std::is_convertible<R, BigInt>::value &&
                              std::is_lvalue_reference<R &&>::value,
                          BigInt>::type friend
  operator+(L &&l, R &&r) {
    BigInt result(std::forward<L>(l));
    result += r;
    return result;
  }
  template <typename L, typename R>
  typename std::enable_if<std::is_convertible<L, BigInt>::value &&
                              std::is_convertible<R, BigInt>::value &&
                              std::is_rvalue_reference<R &&>::value,
                          BigInt>::type friend
  operator+(L &&l, R &&r) {
    BigInt result(std::move(r));
    result += l;
    return result;
  }

  template <typename L, typename R>
  typename std::enable_if<std::is_convertible<L, BigInt>::value &&
                              std::is_convertible<R, BigInt>::value,
                          BigInt>::type friend
  operator-(L &&l, R &&r) {
    BigInt result(std::forward<L>(l));
    result -= r;
    return result;
  }

  // -------------------- Operators * / % --------------------
  friend pair<BigInt, BigInt> divmod(const BigInt &a1, const BigInt &b1) {
    assert(b1 > 0); // divmod not well-defined for b < 0.

    long long norm = BASE / (b1.a.back() + 1);
    BigInt a = a1.abs() * norm;
    BigInt b = b1.abs() * norm;
    BigInt q = 0, r = 0;
    q.a.resize(a.a.size());

    for (int i = a.a.size() - 1; i >= 0; i--) {
      r *= BASE;
      r += a.a[i];
      long long s1 = r.a.size() <= b.a.size() ? 0 : r.a[b.a.size()];
      long long s2 = r.a.size() <= b.a.size() - 1 ? 0 : r.a[b.a.size() - 1];
      long long d = ((long long)BASE * s1 + s2) / b.a.back();
      r -= b * d;
      while (r < 0) {
        r += b, --d;
      }
      q.a[i] = d;
    }

    q.sign = a1.sign * b1.sign;
    r.sign = a1.sign;
    q.trim();
    r.trim();
    auto res = make_pair(q, r / norm);
    if (res.second < 0)
      res.second += b1;
    return res;
  }
  BigInt operator/(const BigInt &v) const { return divmod(*this, v).first; }

  BigInt operator%(const BigInt &v) const { return divmod(*this, v).second; }

  void operator/=(int v) {
    assert(v > 0); // operator / not well-defined for v <= 0.
    if (llabs(v) >= BASE) {
      *this /= BigInt(v);
      return;
    }
    if (v < 0)
      sign = -sign, v = -v;
    for (int i = (int)a.size() - 1, rem = 0; i >= 0; --i) {
      long long cur = a[i] + rem * (long long)BASE;
      a[i] = (int)(cur / v);
      rem = (int)(cur % v);
    }
    trim();
  }

  BigInt operator/(int v) const {
    assert(v > 0); // operator / not well-defined for v <= 0.

    if (llabs(v) >= BASE) {
      return *this / BigInt(v);
    }
    BigInt res = *this;
    res /= v;
    return res;
  }
  void operator/=(const BigInt &v) { *this = *this / v; }

  long long operator%(long long v) const {
    assert(v > 0); // operator / not well-defined for v <= 0.
    assert(v < BASE);
    int m = 0;
    for (int i = a.size() - 1; i >= 0; --i)
      m = (a[i] + m * (long long)BASE) % v;
    return m * sign;
  }

  void operator*=(int v) {
    if (llabs(v) >= BASE) {
      *this *= BigInt(v);
      return;
    }
    if (v < 0)
      sign = -sign, v = -v;
    for (int i = 0, carry = 0; i < (int)a.size() || carry; ++i) {
      if (i == (int)a.size())
        a.push_back(0);
      long long cur = a[i] * (long long)v + carry;
      carry = (int)(cur / BASE);
      a[i] = (int)(cur % BASE);
      // asm("divl %%ecx" : "=a"(carry), "=d"(a[i]) : "A"(cur), "c"(base));
      /*
       int val;
       __asm {
       lea esi, cur
       mov eax, [esi]
       mov edx, [esi+4]
       mov ecx, base
       div ecx
       mov carry, eax
       mov val, edx;
       }
       a[i] = val;
       */
    }
    trim();
  }

  BigInt operator*(int v) const {
    if (llabs(v) >= BASE) {
      return *this * BigInt(v);
    }
    BigInt res = *this;
    res *= v;
    return res;
  }

  // Convert BASE 10^old --> 10^new.
  static vector<int> convert_base(const vector<int> &a, int old_digits,
                                  int new_digits) {
    vector<long long> p(max(old_digits, new_digits) + 1);
    p[0] = 1;
    for (int i = 1; i < (int)p.size(); i++)
      p[i] = p[i - 1] * 10;
    vector<int> res;
    long long cur = 0;
    int cur_digits = 0;
    for (int i = 0; i < (int)a.size(); i++) {
      cur += a[i] * p[cur_digits];
      cur_digits += old_digits;
      while (cur_digits >= new_digits) {
        res.push_back((long long)(cur % p[new_digits]));
        cur /= p[new_digits];
        cur_digits -= new_digits;
      }
    }
    res.push_back((int)cur);
    while (!res.empty() && !res.back())
      res.pop_back();
    return res;
  }

  void fft(vector<complex<double>> &a, bool invert) const {
    int n = (int)a.size();

    for (int i = 1, j = 0; i < n; ++i) {
      int bit = n >> 1;
      for (; j >= bit; bit >>= 1)
        j -= bit;
      j += bit;
      if (i < j)
        swap(a[i], a[j]);
    }

    for (int len = 2; len <= n; len <<= 1) {
      double ang = 2 * 3.14159265358979323846 / len * (invert ? -1 : 1);
      complex<double> wlen(cos(ang), sin(ang));
      for (int i = 0; i < n; i += len) {
        complex<double> w(1);
        for (int j = 0; j < len / 2; ++j) {
          complex<double> u = a[i + j];
          complex<double> v = a[i + j + len / 2] * w;
          a[i + j] = u + v;
          a[i + j + len / 2] = u - v;
          w *= wlen;
        }
      }
    }
    if (invert)
      for (int i = 0; i < n; ++i)
        a[i] /= n;
  }

  void multiply_fft(const vector<int> &a, const vector<int> &b,
                    vector<int> &res) const {
    vector<complex<double>> fa(a.begin(), a.end());
    vector<complex<double>> fb(b.begin(), b.end());
    int n = 1;
    while (n < (int)max(a.size(), b.size()))
      n <<= 1;
    n <<= 1;
    fa.resize(n);
    fb.resize(n);

    fft(fa, false);
    fft(fb, false);
    for (int i = 0; i < n; ++i)
      fa[i] *= fb[i];
    fft(fa, true);

    res.resize(n);
    long long carry = 0;
    for (int i = 0; i < n; ++i) {
      long long t = (long long)(fa[i].real() + 0.5) + carry;
      carry = t / 1000;
      res[i] = t % 1000;
    }
  }

  BigInt mul_simple(const BigInt &v) const {
    BigInt res;
    res.sign = sign * v.sign;
    res.a.resize(a.size() + v.a.size());
    for (int i = 0; i < (int)a.size(); ++i)
      if (a[i])
        for (int j = 0, carry = 0; j < (int)v.a.size() || carry; ++j) {
          long long cur = res.a[i + j] +
                          (long long)a[i] * (j < (int)v.a.size() ? v.a[j] : 0) +
                          carry;
          carry = (int)(cur / BASE);
          res.a[i + j] = (int)(cur % BASE);
        }
    res.trim();
    return res;
  }

  typedef vector<long long> vll;

  static vll karatsubaMultiply(const vll &a, const vll &b) {
    int n = a.size();
    vll res(n + n);
    if (n <= 32) {
      for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
          res[i + j] += a[i] * b[j];
      return res;
    }

    int k = n >> 1;
    vll a1(a.begin(), a.begin() + k);
    vll a2(a.begin() + k, a.end());
    vll b1(b.begin(), b.begin() + k);
    vll b2(b.begin() + k, b.end());

    vll a1b1 = karatsubaMultiply(a1, b1);
    vll a2b2 = karatsubaMultiply(a2, b2);

    for (int i = 0; i < k; i++)
      a2[i] += a1[i];
    for (int i = 0; i < k; i++)
      b2[i] += b1[i];

    vll r = karatsubaMultiply(a2, b2);
    for (int i = 0; i < (int)a1b1.size(); i++)
      r[i] -= a1b1[i];
    for (int i = 0; i < (int)a2b2.size(); i++)
      r[i] -= a2b2[i];

    for (int i = 0; i < (int)r.size(); i++)
      res[i + k] += r[i];
    for (int i = 0; i < (int)a1b1.size(); i++)
      res[i] += a1b1[i];
    for (int i = 0; i < (int)a2b2.size(); i++)
      res[i + n] += a2b2[i];
    return res;
  }

  BigInt mul_karatsuba(const BigInt &v) const {
    vector<int> a6 = convert_base(this->a, BASE_DIGITS, 6);
    vector<int> b6 = convert_base(v.a, BASE_DIGITS, 6);
    vll a(a6.begin(), a6.end());
    vll b(b6.begin(), b6.end());
    while (a.size() < b.size())
      a.push_back(0);
    while (b.size() < a.size())
      b.push_back(0);
    while (a.size() & (a.size() - 1))
      a.push_back(0), b.push_back(0);
    vll c = karatsubaMultiply(a, b);
    BigInt res;
    res.sign = sign * v.sign;
    long long carry = 0;
    for (int i = 0; i < (int)c.size(); i++) {
      long long cur = c[i] + carry;
      res.a.push_back((int)(cur % 1000000));
      carry = cur / 1000000;
    }
    res.a = convert_base(res.a, 6, BASE_DIGITS);
    res.trim();
    return res;
  }

  void operator*=(const BigInt &v) { *this = *this * v; }
  BigInt operator*(const BigInt &v) const {
    if (a.size() * v.a.size() <= 1000111)
      return mul_simple(v);
    if (a.size() > 500111 || v.a.size() > 500111)
      return mul_fft(v);
    return mul_karatsuba(v);
  }

  BigInt mul_fft(const BigInt &v) const {
    BigInt res;
    res.sign = sign * v.sign;
    multiply_fft(convert_base(a, BASE_DIGITS, 3),
                 convert_base(v.a, BASE_DIGITS, 3), res.a);
    res.a = convert_base(res.a, 3, BASE_DIGITS);
    res.trim();
    return res;
  }

  // -------------------- Misc --------------------
  BigInt abs() const {
    BigInt res = *this;
    res.sign *= res.sign;
    return res;
  }
  void trim() {
    while (!a.empty() && !a.back())
      a.pop_back();
    if (a.empty())
      sign = 1;
  }

  bool isZero() const { return a.empty() || (a.size() == 1 && !a[0]); }

  friend BigInt gcd(const BigInt &a, const BigInt &b) {
    return b.isZero() ? a : gcd(b, a % b);
  }
  friend BigInt lcm(const BigInt &a, const BigInt &b) {
    return a / gcd(a, b) * b;
  }

  friend BigInt sqrt(const BigInt &a1) {
    BigInt a = a1;
    while (a.a.empty() || a.a.size() % 2 == 1)
      a.a.push_back(0);

    int n = a.a.size();

    int firstDigit = (int)sqrt((double)a.a[n - 1] * BASE + a.a[n - 2]);
    int norm = BASE / (firstDigit + 1);
    a *= norm;
    a *= norm;
    while (a.a.empty() || a.a.size() % 2 == 1)
      a.a.push_back(0);

    BigInt r = (long long)a.a[n - 1] * BASE + a.a[n - 2];
    firstDigit = (int)sqrt((double)a.a[n - 1] * BASE + a.a[n - 2]);
    int q = firstDigit;
    BigInt res;

    for (int j = n / 2 - 1; j >= 0; j--) {
      for (;; --q) {
        BigInt r1 =
            (r - (res * 2 * BigInt(BASE) + q) * q) * BigInt(BASE) *
                BigInt(BASE) +
            (j > 0 ? (long long)a.a[2 * j - 1] * BASE + a.a[2 * j - 2] : 0);
        if (r1 >= 0) {
          r = r1;
          break;
        }
      }
      res *= BASE;
      res += q;

      if (j > 0) {
        int d1 = res.a.size() + 2 < r.a.size() ? r.a[res.a.size() + 2] : 0;
        int d2 = res.a.size() + 1 < r.a.size() ? r.a[res.a.size() + 1] : 0;
        int d3 = res.a.size() < r.a.size() ? r.a[res.a.size()] : 0;
        q = ((long long)d1 * BASE * BASE + (long long)d2 * BASE + d3) /
            (firstDigit * 2);
      }
    }

    res.trim();
    return res / norm;
  }
};
ll n, m, q, k, r;

void solve() {
  cin >> n;
  vi tab(n);
  cin >> tab;
  tab.pb(-INF);

  BigInt kasa = 1000;
  BigInt akcje = 0;

  int poz = 0;
  bool szukam_min = 1;

  while (poz < n) {
    // cout << poz << ' ' << kasa << ' ' << akcje << endl;
    if (szukam_min) {
      if (tab[poz] >= tab[poz + 1]) {

      } else {
        // sprzedaje
        BigInt ile = kasa / tab[poz];
        akcje += ile;
        kasa = kasa % tab[poz];
        szukam_min = false;
      }
      poz++;
    } else {
      if (tab[poz] <= tab[poz + 1]) {

      } else {
        BigInt ile = akcje * tab[poz];
        akcje = 0;
        kasa += ile;
        szukam_min = true;
      }
      poz++;
    }
  }
  cout << kasa << '\\n';
}

signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);

  q = 1;
  // cin >> q;

  for (int i = 1; i <= q; i++)
    solve();
}

Error: -11

Fixed submission:

// Marcin Knapik
#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

using namespace std;

// #include <ext/pb_ds/assoc_container.hpp> // order_of_key
// #include <ext/pb_ds/tree_policy.hpp> // find by order
// using namespace __gnu_pbds;
// #define ordered_set tree< int , null_type,less< int >,
// rb_tree_tag,tree_order_statistics_node_update>

// const ll MAX_LL = 0xFFFFFFFFFFFFFFFF;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define losuj(a, b) uniform_int_distribution<ll>(a, b)(rng)

typedef long double ld;
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
#define pll pair<long long, long long>
#define vpll vector<pll>
#define ull unsigned long long

#define sz(a) (int)(a).size()
#define pb push_back
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define FOR(i, a) for (int i = 0; i < (a); i++)
#define f first
#define s second

template <class T> inline bool setmin(T &a, T b) {
  if (a > b)
    return a = b, 1;
  return 0;
}
template <class T> inline bool setmax(T &a, T b) {
  if (a < b)
    return a = b, 1;
  return 0;
}

template <class T> inline T fast(T a, T b, T mod) {
  ll res = 1;
  while (b) {
    if (b & 1)
      res = (res * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return res;
}
template <class T> istream &operator>>(istream &os, vector<T> &container) {
  for (auto &u : container)
    os >> u;
  return os;
}
template <class T>
ostream &operator<<(ostream &os, const vector<T> &container) {
  for (auto &u : container)
    os << u << " ";
  return os;
}
template <class T> inline T gcd(T a, T b) {
  while (b)
    swap(a %= b, b);
  return abs(a);
}

const ll INF = 1e9 + 7;
const ll mod = 998244353;
const ll BIG_INF = 1e18 + 7;
const ll N = 1e6 + 7;
const ll T = 1 << 20;
const ld inf = 1e18;

ll n, m, q, k, r;
const int MAXI = (200 * 80 + 1000 + 1) * 10;
ll dp[81][MAXI];

void solve() {
  cin >> n;
  for (int i = 0; i < 81; i++)
    FOR(j, MAXI)
  dp[i][j] = -INF;
  dp[0][0] = 1000;

  for (int i = 1; i <= n; i++) {
    ll temp;
    cin >> temp;

    for (int j = 0; j < MAXI; j++) {
      ll ile = dp[i - 1][j];
      if (ile >= 0) {
        setmax(dp[i][j], dp[i - 1][j]);
        setmax(dp[i][0], ile + temp * j);
        int kup = ile / temp;
        setmax(dp[i][j + kup], ile - kup * temp);
      }
    }
  }
  cout << dp[n][0] << '\\n';
}

signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);

  q = 1;
  // cin >> q;

  for (int i = 1; i <= q; i++)
    solve();
}