Submission #1251370

#	Time	Username	Problem	Language	Result	Execution time	Memory
1251370		Benq	Obstacles for a Llama (IOI25_obstacles)	C++20	83 / 100	365 ms	21604 KiB

obstacles

#include "obstacles.h"

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <climits>
#include <cmath>
#include <complex>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <vector>
using namespace std;

using ll = long long;
using db = long double; // or double, if TL is tight
using str = string;     // yay python!

// pairs
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
#define mp make_pair
#define f first
#define s second

#define tcT template <class T
#define tcTU tcT, class U
// ^ lol this makes everything look weird but I'll try it
tcT > using V = vector<T>;
tcT, size_t SZ > using AR = array<T, SZ>;
using vi = V<int>;
using vb = V<bool>;
using vl = V<ll>;
using vd = V<db>;
using vs = V<str>;
using vpi = V<pi>;
using vpl = V<pl>;
using vpd = V<pd>;

// vectors
#define sz(x) int(size(x))
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define sor(x) sort(all(x))
#define rsz resize
#define ins insert
#define pb push_back
#define eb emplace_back
#define ft front()
#define bk back()

#define lb lower_bound
#define ub upper_bound
tcT > int lwb(const V<T> &a, const T &b) { return int(lb(all(a), b) - bg(a)); }
tcT > int upb(const V<T> &a, const T &b) { return int(ub(all(a), b) - bg(a)); }

// loops
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); --i)
#define R0F(i, a) ROF(i, 0, a)
#define rep(a) F0R(_, a)
#define each(a, x) for (auto &a : x)

const int MOD = 998244353; // 1e9+7;
const int MX = (int)2e5 + 5;
const ll BIG = 1e18; // not too close to LLONG_MAX
const db PI = acos((db)-1);
const int dx[4]{1, 0, -1, 0}, dy[4]{0, 1, 0, -1}; // for every grid problem!!
mt19937_64
    rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
template <class T> using pqg = priority_queue<T, vector<T>, greater<T>>;

// bitwise ops
// also see https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html
constexpr int pct(int x) { return __builtin_popcount(x); } // # of bits set
constexpr int bits(
    int x) { // assert(x >= 0); // make C++11 compatible until USACO updates ...
  return x == 0 ? 0 : 31 - __builtin_clz(x);
} // floor(log2(x))
constexpr int p2(int x) { return 1 << x; }
constexpr int msk2(int x) { return p2(x) - 1; }

ll cdiv(ll a, ll b) {
  return a / b + ((a ^ b) > 0 && a % b);
} // divide a by b rounded up
ll fdiv(ll a, ll b) {
  return a / b - ((a ^ b) < 0 && a % b);
} // divide a by b rounded down

tcT > bool ckmin(T &a, const T &b) {
  return b < a ? a = b, 1 : 0;
} // set a = min(a,b)
tcT > bool ckmax(T &a, const T &b) {
  return a < b ? a = b, 1 : 0;
} // set a = max(a,b)

tcTU > T fstTrue(T lo, T hi, U f) {
  ++hi;
  assert(lo <= hi); // assuming f is increasing
  while (lo < hi) { // find first index such that f is true
    T mid = lo + (hi - lo) / 2;
    f(mid) ? hi = mid : lo = mid + 1;
  }
  return lo;
}
tcTU > T lstTrue(T lo, T hi, U f) {
  --lo;
  assert(lo <= hi); // assuming f is decreasing
  while (lo < hi) { // find first index such that f is true
    T mid = lo + (hi - lo + 1) / 2;
    f(mid) ? lo = mid : hi = mid - 1;
  }
  return lo;
}
tcT > void remDup(vector<T> &v) { // sort and remove duplicates
  sort(all(v));
  v.erase(unique(all(v)), end(v));
}
tcTU > void safeErase(T &t, const U &u) {
  auto it = t.find(u);
  assert(it != end(t));
  t.erase(it);
}

inline namespace IO {
#define SFINAE(x, ...)                                                         \
  template <class, class = void> struct x : std::false_type {};                \
  template <class T> struct x<T, std::void_t<__VA_ARGS__>> : std::true_type {}

SFINAE(DefaultI, decltype(std::cin >> std::declval<T &>()));
SFINAE(DefaultO, decltype(std::cout << std::declval<T &>()));
SFINAE(IsTuple, typename std::tuple_size<T>::type);
SFINAE(Iterable, decltype(std::begin(std::declval<T>())));

template <auto &is> struct Reader {
  template <class T> void Impl(T &t) {
    if constexpr (DefaultI<T>::value)
      is >> t;
    else if constexpr (Iterable<T>::value) {
      for (auto &x : t)
        Impl(x);
    } else if constexpr (IsTuple<T>::value) {
      std::apply([this](auto &...args) { (Impl(args), ...); }, t);
    } else
      static_assert(IsTuple<T>::value, "No matching type for read");
  }
  template <class... Ts> void read(Ts &...ts) { ((Impl(ts)), ...); }
};

template <class... Ts> void re(Ts &...ts) { Reader<cin>{}.read(ts...); }
#define def(t, args...)                                                        \
  t args;                                                                      \
  re(args);

template <auto &os, bool debug, bool print_nd> struct Writer {
  string comma() const { return debug ? "," : ""; }
  template <class T> constexpr char Space(const T &) const {
    return print_nd && (Iterable<T>::value or IsTuple<T>::value) ? '\n' : ' ';
  }
  template <class T> void Impl(T const &t) const {
    if constexpr (DefaultO<T>::value)
      os << t;
    else if constexpr (Iterable<T>::value) {
      if (debug)
        os << '{';
      int i = 0;
      for (auto &&x : t)
        ((i++) ? (os << comma() << Space(x), Impl(x)) : Impl(x));
      if (debug)
        os << '}';
    } else if constexpr (IsTuple<T>::value) {
      if (debug)
        os << '(';
      std::apply(
          [this](auto const &...args) {
            int i = 0;
            (((i++) ? (os << comma() << " ", Impl(args)) : Impl(args)), ...);
          },
          t);
      if (debug)
        os << ')';
    } else
      static_assert(IsTuple<T>::value, "No matching type for print");
  }
  template <class T> void ImplWrapper(T const &t) const {
    if (debug)
      os << "\033[0;31m";
    Impl(t);
    if (debug)
      os << "\033[0m";
  }
  template <class... Ts> void print(Ts const &...ts) const {
    ((Impl(ts)), ...);
  }
  template <class F, class... Ts>
  void print_with_sep(const std::string &sep, F const &f,
                      Ts const &...ts) const {
    ImplWrapper(f), ((os << sep, ImplWrapper(ts)), ...), os << '\n';
  }
  void print_with_sep(const std::string &) const { os << '\n'; }
};

template <class... Ts> void pr(Ts const &...ts) {
  Writer<cout, false, true>{}.print(ts...);
}
template <class... Ts> void ps(Ts const &...ts) {
  Writer<cout, false, true>{}.print_with_sep(" ", ts...);
}
} // namespace IO

inline namespace Debug {
template <typename... Args> void err(Args... args) {
  Writer<cerr, true, false>{}.print_with_sep(" | ", args...);
}
template <typename... Args> void errn(Args... args) {
  Writer<cerr, true, true>{}.print_with_sep(" | ", args...);
}

void err_prefix(str func, int line, string args) {
  cerr << "\033[0;31m\u001b[1mDEBUG\033[0m"
       << " | "
       << "\u001b[34m" << func << "\033[0m"
       << ":"
       << "\u001b[34m" << line << "\033[0m"
       << " - "
       << "[" << args << "] = ";
}

#ifdef LOCAL
#define dbg(args...) err_prefix(__FUNCTION__, __LINE__, #args), err(args)
#define dbgn(args...) err_prefix(__FUNCTION__, __LINE__, #args), errn(args)
#else
#define dbg(...)
#define dbgn(args...)
#endif

const auto beg_time = std::chrono::high_resolution_clock::now();
// https://stackoverflow.com/questions/47980498/accurate-c-c-clock-on-a-multi-core-processor-with-auto-overclock?noredirect=1&lq=1
double time_elapsed() {
  return chrono::duration<double>(std::chrono::high_resolution_clock::now() -
                                  beg_time)
      .count();
}
} // namespace Debug

inline namespace FileIO {
void setIn(str s) { freopen(s.c_str(), "r", stdin); }
void setOut(str s) { freopen(s.c_str(), "w", stdout); }
void setIO(str s = "") {
  cin.tie(0)->sync_with_stdio(0); // unsync C / C++ I/O streams
  cout << fixed << setprecision(12);
  // cin.exceptions(cin.failbit);
  // throws exception when do smth illegal
  // ex. try to read letter into int
  if (sz(s))
    setIn(s + ".in"), setOut(s + ".out"); // for old USACO
}
} // namespace FileIO

int N, M;
using U = uint64_t;
V<U> hsh;

void initialize(std::vector<int> T, std::vector<int> H) {
  N = sz(T);
  M = sz(H);
  vi l_to_r(M, -1), r_to_l(M, -1);

  map<pi, int> ivals;
  set<pair<int, pi>> remaining_ivals;
  auto add_interval = [&](int l, int r, int h) {
    dbg("ADD INTERVAL", l, r, h);
    ivals[{l, r}] = h;
    remaining_ivals.ins({h, {l, r}});
    l_to_r.at(l) = r;
    r_to_l.at(r) = l;
  };

  auto del_ival = [&](int l, int r) {
    dbg("DEL IVAL", l, r);
    auto it = ivals.find({l, r});
    assert(it != end(ivals));
    int h = it->s;
    ivals.erase(it);

    auto it2 = remaining_ivals.find({h, {l, r}});
    if (it2 != end(remaining_ivals))
      remaining_ivals.erase(it2);

    dbg("DONE IVAL");
    return h;
  };

  dbg("XX");

  priority_queue<pi, vpi, greater<pi>> H_todo;

  // min H in range
  for (int r = 0; r < M;) {
    if (H.at(r) >= T.at(0)) {
      H_todo.push({H.at(r), r});
      ++r;
      continue;
    }
    int l = r;
    int min_H = H.at(l);
    while (r + 1 < sz(H) && T.at(0) > H.at(r + 1)) {
      ++r;
      ckmin(min_H, H.at(r));
    }
    add_interval(l, r, min_H);
    ++r;
  }

  dbg("AA");

  vpi bounded;
  F0R(i, N) {
    // dbg("DOING", i);
    while (sz(remaining_ivals) && rbegin(remaining_ivals)->f >= T.at(i)) {
      dbg("KILL", *rbegin(remaining_ivals));
      bounded.pb(rbegin(remaining_ivals)->s);
      remaining_ivals.erase(prev(end(remaining_ivals)));
    }
    while (sz(H_todo) && H_todo.top().f < T.at(i)) {
      int l = H_todo.top().s;
      int r = H_todo.top().s;
      int h = H_todo.top().f;
      H_todo.pop();
      // dbg("PROC", l, r, h);

      if (l > 0 && r_to_l.at(l - 1) != -1) {
        int l1 = r_to_l.at(l - 1);
        // dbg("GOT", l1, l - 1);
        ckmin(h, del_ival(l1, l - 1));
        r_to_l.at(l - 1) = -1;
        l = l1;
      }
      if (r < M - 1 && l_to_r.at(r + 1) != -1) {
        int r1 = l_to_r.at(r + 1);
        // dbg("GOT", r + 1, r1);
        ckmin(h, del_ival(r + 1, r1));
        l_to_r.at(r + 1) = -1;
        r = r1;
      }
      add_interval(l, r, h);
    }
  }
  while (sz(remaining_ivals)) {
    bounded.pb(rbegin(remaining_ivals)->s);
    remaining_ivals.erase(prev(end(remaining_ivals)));
  }

  hsh.rsz(M + 1);
  for (auto [l, r] : bounded) {
    U u = rng();
    hsh.at(l) ^= u;
    hsh.at(r + 1) ^= u;
  }
  F0R(i, M) hsh.at(i + 1) ^= hsh.at(i);

  // dbg("BB");
  // dbg(bounded);
}

bool can_reach(int L, int R, int S, int D) {
  assert(L == 0 && R == M - 1);
  return hsh.at(S) == hsh.at(D);
  // return false;
}

Compilation message (stderr)

obstacles.cpp: In function 'void FileIO::setIn(str)':
obstacles.cpp:258:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  258 | void setIn(str s) { freopen(s.c_str(), "r", stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
obstacles.cpp: In function 'void FileIO::setOut(str)':
obstacles.cpp:259:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  259 | void setOut(str s) { freopen(s.c_str(), "w", stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 10 / 10
• Subtask 2: 14 / 14
• Subtask 3: 13 / 13
• Subtask 4: 21 / 21
• Subtask 5: 25 / 25
• Subtask 6: 0 / 17