Submission #1252169

#	Time	Username	Problem	Language	Result	Execution time	Memory
1252169		Benq	Migrations (IOI25_migrations)	C++20	97.45 / 100	32 ms	1332 KiB

migrations

#include "migrations.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 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

const int D = 14;
V<AR<int, 14>> p;
vi depth;
AR<int, 2> diameter;
AR<vi, 2> cands;

int lca(int a, int b) {
	if (depth.at(a) < depth.at(b)) swap(a, b);
	R0F(d, D) if ((depth.at(a) - depth.at(b)) & (1 << d)) a = p.at(a).at(d);
	if (a == b) return a;
	R0F(d, D) if (p.at(a).at(d) != p.at(b).at(d)) {
		a = p.at(a).at(d);
		b = p.at(b).at(d);
	}
	return p.at(a).at(0);
}

int dist(int a, int b) {
	return depth.at(a) + depth.at(b) - 2 * depth.at(lca(a, b));
}

int getpot(pi p, int cons = 1) { return (p.f + cons) * (p.s + cons); }

vi extract(vi v, int parts, int ret) {
	assert(sz(v));
	while (sz(v) % parts) v.pb(v.bk);
	assert(0 <= ret && ret < parts);
	return vi(begin(v) + sz(v) / parts * ret,
	          begin(v) + sz(v) / parts * (ret + 1));
}

int idx(vi &v, int goal, int parts) {
	dbg("IDX", sz(v), v.ft, goal, parts);
	assert(sz(v));
	while (sz(v) % parts) v.pb(v.bk);
	int i = 0;
	while (v.at(i) != goal) {
		++i;
		assert(i < sz(v));
	}

	int ret = i * parts / sz(v);
	v = extract(v, parts, ret);
	return ret;
}

// 10000, 182 (1 move)
// 553, 25 (1 move)
// 81, 6 (1 move)
// 23, rest (6 moves)

vi cuts;

void init_cuts(int N) {
	cuts = {N};              // cuts[4]
	cuts.pb(cuts.bk - 6);    // cuts[3]
	cuts.pb(cuts.bk - 6);    // cuts[2]
	cuts.pb(cuts.bk - 25);   // cuts[1]
	cuts.pb(cuts.bk - 182);  // cuts[0]
	reverse(all(cuts));
	assert(sz(cuts) == 5);
}

pi pos_val;

int send_message(int N, int i, int Pi) {
	if (i == 1) {
		p.eb(), depth.eb();
		F0R(j, 2) cands.at(j).pb(0);
		init_cuts(N);
	}

	p.eb();
	p.bk.at(0) = Pi;
	depth.pb(depth.at(Pi) + 1);
	FOR(d, 1, D) p.bk.at(d) = p.at(p.bk.at(d - 1)).at(d - 1);
	assert(sz(p) == i + 1);

	auto old_diameter = diameter;
	F0R(j, 2) {
		if (dist(i, diameter.at(j)) > dist(diameter.at(0), diameter.at(1))) {
			diameter.at(j ^ 1) = i;
			break;
		}
	}

	int cut_idx = 0;
	while (cuts.at(cut_idx + 1) <= i) ++cut_idx;
	if (cut_idx > 0 && cuts.at(cut_idx) == i) {
		FOR(j, cuts.at(cut_idx - 1), cuts.at(cut_idx)) {
			cands.at(0).pb(j);
			cands.at(1).pb(j);
		}
	}

	int msg = 0;
	if (i >= cuts.at(3)) {
		int j = sz(cands[0]) < sz(cands[1]);
		int s0 = sz(cands.at(j)), s1 = sz(cands.at(j ^ 1));
		dbg("part 1", i, s0, s1, diameter);
		if (mp(s0, s1) == mp(2, 2)) {
			// cands[0][0], cands[0][1]
			// cands[1][0], cands[1][1]
			if (diameter.at(1) == i) {
				cands.at(1) = {i};
				msg = 1;
			} else if (diameter.at(0) == i) {
				cands.at(0) = {i};
				msg = 2;
			} else if (diameter.at(0) == cands.at(0).at(0)) {
				cands.at(0) = {cands.at(0).at(0)};
				msg = 3;
			} else {
				assert(diameter.at(0) == cands.at(0).at(1));
				cands.at(0) = {cands.at(0).at(1)};
				msg = 4;
			}
		} else if (mp(s0, s1) == mp(2, 1)) {
			AR<int, 2> actual{diameter.at(j), diameter.at(j ^ 1)};
			V<AR<int, 2>> all_pairs{{cands[j][0], cands[j ^ 1][0]},
			                        {cands[j][1], cands[j ^ 1][0]},
			                        {cands[j][0], i},
			                        {cands[j][1], i},
			                        {i, cands[j ^ 1][0]}};
			while (all_pairs.at(msg) != actual) ++msg;
			cands.at(j) = {all_pairs.at(msg).at(0)};
			cands.at(j ^ 1) = {all_pairs.at(msg).at(1)};
		} else if (mp(s0, s1) == mp(1, 1)) {
			assert(false);
		} else {
			pi c0{cdiv(s0 + 1, 5), s1 + 1};
			pi c1{cdiv(s0 + 1, 2), cdiv(s1 + 1, 2)};
			F0R(j, 2) cands.at(j).pb(i);
			if (getpot(c1) <= getpot(c0)) {
				return 2 * idx(cands.at(j), diameter.at(j), 2) +
				       idx(cands.at(j ^ 1), diameter.at(j ^ 1), 2);
			} else {
				return idx(cands.at(j), diameter.at(j), 5);
			}
		}
	} else if (i >= cuts.at(0)) {
		dbg(i, cut_idx);
		if (i == cuts.at(cut_idx)) {
			assert(sz(cands.at(0)) == sz(cands.at(1)));
			int space = cuts.at(cut_idx + 1) - cuts.at(cut_idx);
			int num_cands = 4 * space + 1;
			int sqrt_cands = sqrt(num_cands);
			int to_encrypt = 0;
			F0R(j, 2) {
				to_encrypt = sqrt_cands * to_encrypt +
				             idx(cands.at(j), old_diameter.at(j), sqrt_cands);
			}

			if (to_encrypt == 4 * space) {
				pos_val = {-1, -1};
			} else {
				pos_val = {i + to_encrypt / 4, 1 + to_encrypt % 4};
			}
			dbg("ENC", i, to_encrypt, pos_val);
		}
		if (i == pos_val.f) {
			assert(1 <= pos_val.s && pos_val.s <= 4);
			msg = pos_val.s;
		}
	} else {
		F0R(j, 2) cands.at(j).pb(i);
	}
	if (i == N - 1) {
		F0R(j, 2) {
			assert(sz(cands.at(j)) == 1);
			assert(cands.at(j).ft == diameter.at(j));
		}
	}
	return msg;
}

std::pair<int, int> longest_path(std::vector<int> S) {
	p = {};
	depth = {};
	diameter = {};
	cands = {};

	int N = sz(S);
	init_cuts(N);

	F0R(i, N) {
		int cut_idx = 0;
		while (cuts.at(cut_idx + 1) <= i) ++cut_idx;
		if (cut_idx > 0 && cuts.at(cut_idx) == i) {
			int space = cuts.at(cut_idx) - cuts.at(cut_idx - 1);
			int num_cands = 4 * space + 1;
			int sqrt_cands = sqrt(num_cands);
			int to_encrypt = 0;

			if (pos_val == mp(-1, -1)) to_encrypt = 4 * space;
			else {
				to_encrypt =
				    (pos_val.f - cuts.at(cut_idx - 1)) * 4 + (pos_val.s - 1);
			}

			assert(0 <= to_encrypt && to_encrypt < num_cands);
			AR<int, 2> idx{to_encrypt / sqrt_cands, to_encrypt % sqrt_cands};
			dbg("DEC", i, cut_idx, to_encrypt, idx, pos_val);

			F0R(j, 2) cands.at(j) = extract(cands.at(j), sqrt_cands, idx.at(j));

			FOR(j, cuts.at(cut_idx - 1), cuts.at(cut_idx)) {
				cands.at(0).pb(j);
				cands.at(1).pb(j);
			}
		}

		int msg = S.at(i);
		if (i >= cuts.at(3)) {
			int j = sz(cands[0]) < sz(cands[1]);
			int s0 = sz(cands.at(j)), s1 = sz(cands.at(j ^ 1));
			dbg("part 2", i, s0, s1);

			if (mp(s0, s1) == mp(2, 2)) {
				// cands[0][0], cands[0][1]
				// cands[1][0], cands[1][1]
				if (msg == 1) {
					cands.at(1) = {i};
				} else if (msg == 2) {
					cands.at(0) = {i};
				} else if (msg == 3) {
					cands.at(0) = {cands.at(0).at(0)};
				} else if (msg == 4) {
					cands.at(0) = {cands.at(0).at(1)};
				} else {
					assert(false);
				}
			} else if (mp(s0, s1) == mp(2, 1)) {
				V<AR<int, 2>> all_pairs{{cands[j][0], cands[j ^ 1][0]},
				                        {cands[j][1], cands[j ^ 1][0]},
				                        {cands[j][0], i},
				                        {cands[j][1], i},
				                        {i, cands[j ^ 1][0]}};
				cands.at(j) = {all_pairs.at(msg).at(0)};
				cands.at(j ^ 1) = {all_pairs.at(msg).at(1)};
			} else if (mp(s0, s1) == mp(1, 1)) {
				assert(false);
			} else {
				pi c0{cdiv(s0 + 1, 5), s1 + 1};
				pi c1{cdiv(s0 + 1, 2), cdiv(s1 + 1, 2)};
				F0R(j, 2) cands.at(j).pb(i);
				if (getpot(c1) <= getpot(c0)) {
					int idx_j = msg / 2;
					int idx_op = msg % 2;
					cands.at(j) = extract(cands.at(j), 2, idx_j);
					cands.at(j ^ 1) = extract(cands.at(j ^ 1), 2, idx_op);
				} else {
					// c0 is better
					cands.at(j) = extract(cands.at(j), 5, msg);
				}
			}
		} else if (i >= cuts.at(0)) {
			if (i == cuts.at(cut_idx)) { pos_val = {-1, -1}; }
			if (msg != 0) {
				assert(pos_val == mp(-1, -1));
				pos_val = {i, msg};
			}
		} else {
			assert(msg == 0);
			F0R(j, 2) cands.at(j).pb(i);
		}
		if (i == N - 1) {
			F0R(j, 2) assert(sz(cands.at(j)) == 1);
			return {cands.at(0).ft, cands.at(1).ft};
		}
	}
	assert(false);
}

Compilation message (stderr)

migrations.cpp: In function 'void FileIO::setIn(str)':
migrations.cpp:248:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  248 | void setIn(str s) { freopen(s.c_str(), "r", stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
migrations.cpp: In function 'void FileIO::setOut(str)':
migrations.cpp:249:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  249 | void setOut(str s) { freopen(s.c_str(), "w", stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 30 / 30
• Subtask 2: 67.4511 / 70