Submission #841759

#	Time	Username	Problem	Language	Result	Execution time	Memory
841759		Benq	Beech Tree (IOI23_beechtree)	C++17	23 / 100	2051 ms	39908 KiB

beechtree

#include "beechtree.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
// oops size(x), rbegin(x), rend(x) need C++17
#define sz(x) int((x).size())
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define rall(x) x.rbegin(), x.rend()
#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(V<T> &a, const T &b) { return int(lb(all(a), b) - bg(a)); }
tcT > int upb(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 = (int)1e9 + 7;  // 998244353;
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 <class T> constexpr char Space(const T &) {
	return (Iterable<T>::value or IsTuple<T>::value) ? '\n' : ' ';
}

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> struct Writer {
	string comma() const { return debug ? "," : ""; }
	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>{}.print(ts...);
}
template <class... Ts> void ps(Ts const &...ts) {
	Writer<cout, false>{}.print_with_sep(" ", ts...);
}
}  // namespace IO

inline namespace Debug {
template <typename... Args> void err(Args... args) {
	Writer<cerr, 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)
#else
#define dbg(...)
#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

/**
 * Description: wraps a lambda so it can call itself
 * Source: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0200r0.html
 */

namespace std {

template <class Fun> class y_combinator_result {
	Fun fun_;

  public:
	template <class T>
	explicit y_combinator_result(T &&fun) : fun_(std::forward<T>(fun)) {}

	template <class... Args> decltype(auto) operator()(Args &&...args) {
		return fun_(std::ref(*this), std::forward<Args>(args)...);
	}
};

template <class Fun> decltype(auto) y_combinator(Fun &&fun) {
	return y_combinator_result<std::decay_t<Fun>>(std::forward<Fun>(fun));
}

}  // namespace std

void y_comb_demo() {
	cout << y_combinator([](auto gcd, int a, int b) -> int {
		return b == 0 ? a : gcd(b, a % b);
	})(20, 30)
	     << "\n";  // outputs 10
}

/**
 * Description: Disjoint Set Union with path compression
 * and union by size. Add edges and test connectivity.
 * Use for Kruskal's or Boruvka's minimum spanning tree.
 * Time: O(\alpha(N))
 * Source: CSAcademy, KACTL
 * Verification: *
 */

struct DSU {
	vi e;
	void init(int N) { e = vi(N, -1); }
	int get(int x) { return e[x] < 0 ? x : e[x] = get(e[x]); }
	bool sameSet(int a, int b) { return get(a) == get(b); }
	int size(int x) { return -e[get(x)]; }
	bool unite(int x, int y) {  // union by size
		x = get(x), y = get(y);
		if (x == y) return 0;
		if (e[x] > e[y]) swap(x, y);
		e[x] += e[y];
		e[y] = x;
		return 1;
	}
};

/**tcT> T kruskal(int N, vector<pair<T,pi>> ed) {
    sort(all(ed));
    T ans = 0; DSU D; D.init(N); // edges that unite are in MST
    each(a,ed) if (D.unite(a.s.f,a.s.s)) ans += a.f;
    return ans;
}*/

std::vector<int> beechtree(int N, int M, std::vector<int> P,
                           std::vector<int> C) {
	// vi depth(N);
	V<vi> children(N);
	FOR(i, 1, N) children.at(P[i]).pb(i);
	// vi dist(N);
	// FOR(i, 1, N) {
	// 	if (szchildren.at(P[i]) > children.at(i)) {
	// 		dist[i] = 1;
	// 	} else {
	// 		dist[i] = dist[P[i]] + 1;
	// 	}
	// }
	// dbg(dist);
	vi st(N), en(N);
	int nxt = 0;
	y_combinator([&](auto self, int x) -> void {
		st.at(x) = nxt++;
		for (int y : children[x]) self(y);
		en.at(x) = nxt++;
	})(0);
	auto is_anc = [&](int x, int y) {
		return st[x] <= st[y] && en[y] <= en[x];
	};
	assert(nxt == 2 * N);
	vi ret;
	F0R(i, N) {
		vi desc;
		FOR(j, i + 1, N) if (is_anc(i, j)) { desc.pb(j); }
		sort(all(desc),
		     [&](int x, int y) { return sz(children[x]) > sz(children[y]); });
		desc.ins(begin(desc), i);
		map<int, vi> edges;
		for (int x : desc)
			if (x != i) edges[C[x]].pb(P[x]);
		bool ok = true;
		for (auto [_, v] : edges) {
			if (set<int>(begin(desc), begin(desc) + sz(v)) !=
			    set<int>(all(v))) {
				ok = false;
			}
		}
		if (ok) {
			vi deg(N);
			F0R(i, N) deg[i] = sz(children[i]);
			deg[i] = N;
			DSU D;
			D.init(N * N);
			auto hsh = [&](int x, int y) { return N * x + y; };
			for (int a : desc)
				for (int b : desc)
					if (a != i && b != i && C[a] == C[b] && a != b) {
						D.unite(hsh(a, b), hsh(P[a], P[b]));
					}
			vb active(N * N);
			for (int x : desc)
				for (int y : desc)
					if (deg[x] < deg[y]) { active[D.get(hsh(x, y))] = 1; }
			for (int x : desc)
				for (int y : desc) {
					if (active[D.get(hsh(x, y))] && active[D.get(hsh(y, x))]) {
						ok = false;
					}
				}
			for (int x : desc)
				for (int y : desc)
					if (is_anc(x, y) && active[D.get(hsh(x, y))]) {
						ok = false;
					}
		}
		ret.pb(ok);
	}
	return ret;
}

Compilation message (stderr)

beechtree.cpp: In function 'void FileIO::setIn(str)':
beechtree.cpp:244:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  244 | void setIn(str s) { freopen(s.c_str(), "r", stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
beechtree.cpp: In function 'void FileIO::setOut(str)':
beechtree.cpp:245:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  245 | void setOut(str s) { freopen(s.c_str(), "w", stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 0: 0 / 0
• Subtask 1: 9 / 9
• Subtask 2: 0 / 5
• Subtask 3: 0 / 9
• Subtask 4: 0 / 8
• Subtask 5: 14 / 14
• Subtask 6: 0 / 14
• Subtask 7: 0 / 12
• Subtask 8: 0 / 17
• Subtask 9: 0 / 12