Submission #973048

#	Time	Username	Problem	Language	Result	Execution time	Memory
973048		arush_agu	Odd-even (IZhO11_oddeven)	C++17	100 / 100	1 ms	460 KiB

oddeven

#include <ostream>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#ifdef DEBUG
#include <time.h>
#endif

#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x)                                                                 \
  {                                                                            \
    ++recur_depth;                                                             \
    auto x_ = x;                                                               \
    --recur_depth;                                                             \
    cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":"           \
         << __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl;         \
  }
#else
#define dbg(x)
#endif

using namespace std;
using namespace __gnu_pbds;

typedef pair<int, int> ii;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;

typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;

typedef vector<bool> vb;

template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
                         tree_order_statistics_node_update>;

template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
  return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
                                    !is_same<T_container, string>::value,
                                    typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
  os << '{';
  string sep;
  for (const T &x : v)
    os << sep << x, sep = ", ";
  return os << '}';
}

const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e9;
const ld EPS = 1e-9;
constexpr int digits(int base) noexcept {
  return base <= 1 ? 0 : 1 + digits(base / 10);
}

constexpr int base = 1000'000'000;
constexpr int base_digits = digits(base);

constexpr int fft_base =
    10'000; // fft_base^2 * n / fft_base_digits <= 10^15 for double
constexpr int fft_base_digits = digits(fft_base);

struct bigint {
  // value == 0 is represented by empty z
  vector<int> z; // digits

  // sign == 1 <==> value >= 0
  // sign == -1 <==> value < 0
  int sign;

  bigint(long long v = 0) { *this = v; }

  bigint &operator=(long long v) {
    sign = v < 0 ? -1 : 1;
    v *= sign;
    z.clear();
    for (; v > 0; v = v / base)
      z.push_back((int)(v % base));
    return *this;
  }

  bigint(const string &s) { read(s); }

  bigint &operator+=(const bigint &other) {
    if (sign == other.sign) {
      for (int i = 0, carry = 0; i < other.z.size() || carry; ++i) {
        if (i == z.size())
          z.push_back(0);
        z[i] += carry + (i < other.z.size() ? other.z[i] : 0);
        carry = z[i] >= base;
        if (carry)
          z[i] -= base;
      }
    } else if (other != 0 /* prevent infinite loop */) {
      *this -= -other;
    }
    return *this;
  }

  friend bigint operator+(bigint a, const bigint &b) {
    a += b;
    return a;
  }

  bigint &operator-=(const bigint &other) {
    if (sign == other.sign) {
      if ((sign == 1 && *this >= other) || (sign == -1 && *this <= other)) {
        for (int i = 0, carry = 0; i < other.z.size() || carry; ++i) {
          z[i] -= carry + (i < other.z.size() ? other.z[i] : 0);
          carry = z[i] < 0;
          if (carry)
            z[i] += base;
        }
        trim();
      } else {
        *this = other - *this;
        this->sign = -this->sign;
      }
    } else {
      *this += -other;
    }
    return *this;
  }

  friend bigint operator-(bigint a, const bigint &b) {
    a -= b;
    return a;
  }

  bigint &operator*=(int v) {
    if (v < 0)
      sign = -sign, v = -v;
    for (int i = 0, carry = 0; i < z.size() || carry; ++i) {
      if (i == z.size())
        z.push_back(0);
      long long cur = (long long)z[i] * v + carry;
      carry = (int)(cur / base);
      z[i] = (int)(cur % base);
    }
    trim();
    return *this;
  }

  bigint operator*(int v) const { return bigint(*this) *= v; }

  friend pair<bigint, bigint> divmod(const bigint &a1, const bigint &b1) {
    int norm = base / (b1.z.back() + 1);
    bigint a = a1.abs() * norm;
    bigint b = b1.abs() * norm;
    bigint q, r;
    q.z.resize(a.z.size());

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

    q.sign = a1.sign * b1.sign;
    r.sign = a1.sign;
    q.trim();
    r.trim();
    return {q, r / norm};
  }

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

    int n = a.z.size();

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

    bigint r = (long long)a.z[n - 1] * base + a.z[n - 2];
    firstDigit = (int)::sqrt((double)a.z[n - 1] * base + a.z[n - 2]);
    int q = firstDigit;
    bigint res;

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

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

    res.trim();
    return res / norm;
  }

  bigint operator/(const bigint &v) const { return divmod(*this, v).first; }

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

  bigint &operator/=(int v) {
    if (v < 0)
      sign = -sign, v = -v;
    for (int i = (int)z.size() - 1, rem = 0; i >= 0; --i) {
      long long cur = z[i] + rem * (long long)base;
      z[i] = (int)(cur / v);
      rem = (int)(cur % v);
    }
    trim();
    return *this;
  }

  bigint operator/(int v) const { return bigint(*this) /= v; }

  int operator%(int v) const {
    if (v < 0)
      v = -v;
    int m = 0;
    for (int i = (int)z.size() - 1; i >= 0; --i)
      m = (int)((z[i] + m * (long long)base) % v);
    return m * sign;
  }

  bigint &operator*=(const bigint &v) {
    *this = *this * v;
    return *this;
  }

  bigint &operator/=(const bigint &v) {
    *this = *this / v;
    return *this;
  }

  bigint &operator%=(const bigint &v) {
    *this = *this % v;
    return *this;
  }

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

  bool operator!=(const bigint &v) const { return !(*this == v); }

  void trim() {
    while (!z.empty() && z.back() == 0)
      z.pop_back();
    if (z.empty())
      sign = 1;
  }

  bool isZero() const { return z.empty(); }

  friend bigint operator-(bigint v) {
    if (!v.z.empty())
      v.sign = -v.sign;
    return v;
  }

  bigint abs() const { return sign == 1 ? *this : -*this; }

  long long longValue() const {
    long long res = 0;
    for (int i = (int)z.size() - 1; i >= 0; i--)
      res = res * base + z[i];
    return res * sign;
  }

  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;
  }

  void read(const string &s) {
    sign = 1;
    z.clear();
    int pos = 0;
    while (pos < s.size() && (s[pos] == '-' || s[pos] == '+')) {
      if (s[pos] == '-')
        sign = -sign;
      ++pos;
    }
    for (int i = (int)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';
      z.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)
      stream << '-';
    stream << (v.z.empty() ? 0 : v.z.back());
    for (int i = (int)v.z.size() - 2; i >= 0; --i)
      stream << setw(base_digits) << setfill('0') << v.z[i];
    return stream;
  }

  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 < p.size(); i++)
      p[i] = p[i - 1] * 10;
    vector<int> res;
    long long cur = 0;
    int cur_digits = 0;
    for (int v : a) {
      cur += v * p[cur_digits];
      cur_digits += old_digits;
      while (cur_digits >= new_digits) {
        res.push_back(int(cur % p[new_digits]));
        cur /= p[new_digits];
        cur_digits -= new_digits;
      }
    }
    res.push_back((int)cur);
    while (!res.empty() && res.back() == 0)
      res.pop_back();
    return res;
  }

  bigint operator*(const bigint &v) const {
    // if (min(z.size(), v.z.size()) < 150)
    return mul_simple(v);
    // bigint res;
    // res.sign = sign * v.sign;
    // res.z = multiply_bigint(convert_base(z, base_digits, fft_base_digits),
    //                         convert_base(v.z, base_digits, fft_base_digits),
    //                         fft_base);
    // res.z = convert_base(res.z, fft_base_digits, base_digits);
    // res.trim();
    // return res;
  }

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

void solve() {
  string s;
  cin >> s;

  bigint n(0);
  for (int i=0; i<s.size(); i++) n *= 10, n += (s[i] - '0');

  bigint l(1), r(1), ans(1);
  for (int i=0; i<=100; i++) r *= 10;

  while (l <= r) {
    bigint mid = (l + r) / 2;
    if ((mid * (mid + 1)) / 2 >= n) ans = mid, r = mid - 1;
    else l = mid + 1;
  }
  bigint res = bigint(2) * n - ans;
  cout << res << "\n";
}

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);

  clock_t start = clock();

  int test_cases = 1;
  // cin >> test_cases;

  while (test_cases--)
    solve();

#ifdef DEBUG
  cerr << fixed << setprecision(10)
       << "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
       << "s\n";
#endif
  return 0;
}

Compilation message (stderr)

oddeven.cpp: In member function 'bigint& bigint::operator+=(const bigint&)':
oddeven.cpp:129:36: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  129 |       for (int i = 0, carry = 0; i < other.z.size() || carry; ++i) {
      |                                  ~~^~~~~~~~~~~~~~~~
oddeven.cpp:130:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  130 |         if (i == z.size())
      |             ~~^~~~~~~~~~~
oddeven.cpp:132:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  132 |         z[i] += carry + (i < other.z.size() ? other.z[i] : 0);
      |                          ~~^~~~~~~~~~~~~~~~
oddeven.cpp: In member function 'bigint& bigint::operator-=(const bigint&)':
oddeven.cpp:151:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  151 |         for (int i = 0, carry = 0; i < other.z.size() || carry; ++i) {
      |                                    ~~^~~~~~~~~~~~~~~~
oddeven.cpp:152:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  152 |           z[i] -= carry + (i < other.z.size() ? other.z[i] : 0);
      |                            ~~^~~~~~~~~~~~~~~~
oddeven.cpp: In member function 'bigint& bigint::operator*=(int)':
oddeven.cpp:176:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  176 |     for (int i = 0, carry = 0; i < z.size() || carry; ++i) {
      |                                ~~^~~~~~~~~~
oddeven.cpp:177:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  177 |       if (i == z.size())
      |           ~~^~~~~~~~~~~
oddeven.cpp: In member function 'void bigint::read(const string&)':
oddeven.cpp:359:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  359 |     while (pos < s.size() && (s[pos] == '-' || s[pos] == '+')) {
      |            ~~~~^~~~~~~~~~
oddeven.cpp: In static member function 'static std::vector<int> bigint::convert_base(const std::vector<int>&, int, int)':
oddeven.cpp:393:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  393 |     for (int i = 1; i < p.size(); i++)
      |                     ~~^~~~~~~~~~
oddeven.cpp: In member function 'bigint bigint::mul_simple(const bigint&) const':
oddeven.cpp:430:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  430 |     for (int i = 0; i < z.size(); ++i)
      |                     ~~^~~~~~~~~~
oddeven.cpp:432:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  432 |         for (int j = 0, carry = 0; j < v.z.size() || carry; ++j) {
      |                                    ~~^~~~~~~~~~~~
oddeven.cpp:434:48: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  434 |                           (long long)z[i] * (j < v.z.size() ? v.z[j] : 0) +
      |                                              ~~^~~~~~~~~~~~
oddeven.cpp: In function 'void solve()':
oddeven.cpp:449:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  449 |   for (int i=0; i<s.size(); i++) n *= 10, n += (s[i] - '0');
      |                 ~^~~~~~~~~
oddeven.cpp: In function 'int main()':
oddeven.cpp:467:11: warning: unused variable 'start' [-Wunused-variable]
  467 |   clock_t start = clock();
      |           ^~~~~

• Subtask 1: 100 / 100