Submission #305346

#	Time	Username	Problem	Language	Result	Execution time	Memory
305346		Benq	Counting Mushrooms (IOI20_mushrooms)	C++14	100 / 100	10 ms	632 KiB

mushrooms

#include "mushrooms.h"

#include <bits/stdc++.h>
using namespace std;
 
using ll = long long;
using ld = long double;
using db = double; 
using str = string; // yay python!

using pi = pair<int,int>;
using pl = pair<ll,ll>;
using pd = pair<db,db>;

using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>; 
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>; 
using vpd = vector<pd>;

#define tcT template<class T
// ^ 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>; 

// pairs
#define mp make_pair
#define f first
#define s second

// vectors
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() 
#define sor(x) sort(all(x)) 
#define rsz resize
#define ins insert 
#define ft front() 
#define bk back()
#define pf push_front 
#define pb push_back
#define eb emplace_back 
#define lb lower_bound 
#define ub upper_bound 

// 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 trav(a,x) for (auto& a: x)

const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INF = 1e18; // not too close to LLONG_MAX
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1}; // for every grid problem!!
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); 

// helper funcs
constexpr int pct(int x) { return __builtin_popcount(x); } // # of bits set
constexpr int bits(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) 
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; }

#define tcTU tcT, class U
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 erase(T& t, const U& u) { // don't erase
	auto it = t.find(u); assert(it != end(t));
	t.erase(u); } // element that doesn't exist from (multi)set

// INPUT
#define tcTUU tcT, class ...U
tcT> void re(complex<T>& c);
tcTU> void re(pair<T,U>& p);
tcT> void re(vector<T>& v);
tcT, size_t SZ> void re(AR<T,SZ>& a);

tcT> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
tcTUU> void re(T& t, U&... u) { re(t); re(u...); }

tcT> void re(complex<T>& c) { T a,b; re(a,b); c = {a,b}; }
tcTU> void re(pair<T,U>& p) { re(p.f,p.s); }
tcT> void re(vector<T>& x) { trav(a,x) re(a); }
tcT, size_t SZ> void re(AR<T,SZ>& x) { trav(a,x) re(a); }

// TO_STRING
#define ts to_string
str ts(char c) { return str(1,c); }
str ts(const char* s) { return (str)s; }
str ts(str s) { return s; }
str ts(bool b) { 
	#ifdef LOCAL
		return b ? "true" : "false"; 
	#else 
		return ts((int)b);
	#endif
}
tcT> str ts(complex<T> c) { 
	stringstream ss; ss << c; return ss.str(); }
str ts(vector<bool> v) {
	str res = "{"; F0R(i,sz(v)) res += char('0'+v[i]);
	res += "}"; return res; }
template<size_t SZ> str ts(bitset<SZ> b) {
	str res = ""; F0R(i,SZ) res += char('0'+b[i]);
	return res; }
tcTU> str ts(pair<T,U> p);
tcT> str ts(T v) { // containers with begin(), end()
	#ifdef LOCAL
		bool fst = 1; str res = "{";
		for (const auto& x: v) {
			if (!fst) res += ", ";
			fst = 0; res += ts(x);
		}
		res += "}"; return res;
	#else
		bool fst = 1; str res = "";
		for (const auto& x: v) {
			if (!fst) res += " ";
			fst = 0; res += ts(x);
		}
		return res;

	#endif
}
tcTU> str ts(pair<T,U> p) {
	#ifdef LOCAL
		return "("+ts(p.f)+", "+ts(p.s)+")"; 
	#else
		return ts(p.f)+" "+ts(p.s);
	#endif
}

// OUTPUT
tcT> void pr(T x) { cout << ts(x); }
tcTUU> void pr(const T& t, const U&... u) { 
	pr(t); pr(u...); }
void ps() { pr("\n"); } // print w/ spaces
tcTUU> void ps(const T& t, const U&... u) { 
	pr(t); if (sizeof...(u)) pr(" "); ps(u...); }

// DEBUG
void DBG() { cerr << "]" << endl; }
tcTUU> void DBG(const T& t, const U&... u) {
	cerr << ts(t); if (sizeof...(u)) cerr << ", ";
	DBG(u...); }
#ifdef LOCAL // compile with -DLOCAL, chk -> fake assert
	#define dbg(...) cerr << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
	#define chk(...) if (!(__VA_ARGS__)) cerr << "Line(" << __LINE__ << ") -> function(" \
		 << __FUNCTION__  << ") -> CHK FAILED: (" << #__VA_ARGS__ << ")" << "\n", exit(0);
#else
	#define dbg(...) 0
	#define chk(...) 0
#endif

// FILE I/O
void setIn(str s) { freopen(s.c_str(),"r",stdin); }
void setOut(str s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setIO(str s = "") {
	unsyncIO();
	// 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 USACO
}

// rewriting https://loj.ac/submission/938329

using B = bitset<1000>;

struct solve_log {
	int len, need = 0;
	V<B> seq;
};
V<solve_log> sol;

void genQueries(int k) {
	assert(sz(sol) == k); sol.eb();
	int plen = sol[k-1].len; // previous length
	sol[k].len = (1<<(k-1))-1+2*plen;
	B all; F0R(i,sol[k].len) all[i] = 1;
	sol[k].seq.pb(all); // get all bits
	sol[k].seq.pb(sol[k-1].seq[0]); // get all bits in first block
	FOR(i,1,1<<(k-1)) {
		sol[k].seq.pb(sol[k-1].seq[i]^                (sol[k-1].seq[i]<<plen));
		sol[k].seq.pb(sol[k-1].seq[0]^sol[k-1].seq[i]^(sol[k-1].seq[i]<<plen));
		sol[k].seq.bk[2*plen+i-1] = 1;
	}
	vi bit_cnts; trav(t,sol[k].seq) bit_cnts.pb((int)t.count());
	sort(all(bit_cnts));
	F0R(i,sz(bit_cnts)) ckmax(sol[k].need,2*bit_cnts[i]+1-i);
}

const int MAX_ONE = 1000;
vi dp, from;

void init() {
	sol.eb(); sol[0].len = 1; sol[0].need = 3; sol[0].seq.pb(1);
	FOR(k,1,8) genQueries(k);
	dp.rsz(MAX_ONE), from.rsz(MAX_ONE);
	F0R(i,3) dp[i] = i+1;
	FOR(i,2,MAX_ONE) {
		F0R(k,8) {
			if (dp[i] < sol[k].need) break;
			int ind = i+(1<<k); if (ind >= MAX_ONE) break;
			int num = dp[i]+sol[k].len+(1<<k);
			if (num > dp[ind]) dp[ind] = num, from[ind] = k;
		}
	}
}

const int MAX_Q = 210;

int query_cnt;
int query(vi x) {
	assert(++query_cnt <= MAX_Q);
	return use_machine(x);
}

vi solve(int k, vi res) {
	// dbg("HUH",k,sz(res));
	assert(sz(res) == 1<<k);
	if (k == 0) return res;
	// # of all bits
	// # of all bits in first block

	vi tmp[2];
	tmp[0].pb(res[1]);
	vi ans2;
	FOR(i,1,1<<(k-1)) {
		// a+b
		// tmp[0][0]-a+b+x
		int a = (res[2*i]-res[2*i+1]+tmp[0][0]+1)/2;
		int b = res[2*i]-a;
		int x = res[2*i+1]-(tmp[0][0]-a+b); 
		assert(a >= 0 && b >= 0);
		assert(x == 0 || x == 1);
		tmp[0].pb(a), tmp[1].pb(b);
		ans2.pb(x);
	}
	int bits_left = res[0]-tmp[0][0];
	trav(t,ans2) bits_left -= t;
	tmp[1].insert(begin(tmp[1]),bits_left);
	vi ans0 = solve(k-1,tmp[0]);
	vi ans1 = solve(k-1,tmp[1]);
	ans0.insert(end(ans0),all(ans1));
	ans0.insert(end(ans0),all(ans2));
	return ans0;
}

int count_mushrooms(int n) {
	if (n == 2) return 2-query({0,1});
	init();
	int best_n = 0, best_pos = 0;
	FOR(i,2,MAX_ONE) if (dp[i] <= n) {
		int max_n = dp[i];
		F0R(j,MAX_Q-i) max_n += (dp[i]+j+1)/2;
		if (ckmax(best_n,max_n)) best_pos = i;
	}
	assert(best_n >= n);
	vi seq; for (int i = best_pos; i != 2; i -= 1<<from[i]) seq.pb(from[i]);
	reverse(all(seq));
	vi stor[2]; stor[0] = {0};
	int nex = 1;
	stor[query({0,nex})].pb(nex); nex++;
	stor[query({0,nex})].pb(nex); nex++;
	dbg(stor[0],stor[1],seq,best_pos);
	trav(j,seq) {
		vi id(1<<j), res(1<<j); iota(all(id),0);
		sort(all(id),[&](int x, int y) { 
			return sol[j].seq[x].count() < sol[j].seq[y].count(); });
		// dbg("HA",stor[0],stor[1],);
		F0R(k,1<<j) {
			dbg("HA",sz(stor[0]),sz(stor[1]),k,sol[j].seq[id[k]].count());
			int ind = sz(stor[1]) > sz(stor[0]), c = 0; assert(c < sz(stor[ind]));
			vi cur_x;
			cur_x.pb(nex+sol[j].len+k); cur_x.pb(stor[ind][c++]);
			F0R(i,min(n,sz(sol[j].seq[id[k]]))) if (sol[j].seq[id[k]][i] == 1) {
				dbg("ADDING",ind,i);
				cur_x.pb(nex+i);
				assert(c < sz(stor[ind]));
				cur_x.pb(stor[ind][c++]);
			}
			int q = query(cur_x); if (ind) q = 2*c-1-q;
			res[id[k]] = q/2;
			stor[q&1].pb(nex+sol[j].len+k);
		}
		vi val = solve(j,res);
		F0R(i,sz(val)) stor[val[i]].pb(nex+i);
		nex += sol[j].len+(1<<j);
	}
	int ret = sz(stor[0]);
	while (nex < n) {
		int ind = sz(stor[1]) > sz(stor[0]);
		int r = min(nex+sz(stor[ind]),n);
		vi cur_x; FOR(i,nex,r) cur_x.pb(i), cur_x.pb(stor[ind][i-nex]);
		int q = query(cur_x);
		if (ind) q = 2*(r-nex)-1-q;
		ret += r-nex-(q+1)/2;
		stor[q&1].pb(nex);
		nex = r;
	}
	dbg("OK",ret);
	return ret;
	// std::vector<int> m;
	// for (int i = 0; i < n; i++)
	// 	m.push_back(i);
	// int c1 = use_machine(m);
	// m = {0, 1};
	// int c2 = use_machine(m);
	// return c1+c2;
}

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:179:19: warning: statement has no effect [-Wunused-value]
  179 |  #define dbg(...) 0
      |                   ^
mushrooms.cpp:295:2: note: in expansion of macro 'dbg'
  295 |  dbg(stor[0],stor[1],seq,best_pos);
      |  ^~~
mushrooms.cpp:179:19: warning: statement has no effect [-Wunused-value]
  179 |  #define dbg(...) 0
      |                   ^
mushrooms.cpp:302:4: note: in expansion of macro 'dbg'
  302 |    dbg("HA",sz(stor[0]),sz(stor[1]),k,sol[j].seq[id[k]].count());
      |    ^~~
mushrooms.cpp:179:19: warning: statement has no effect [-Wunused-value]
  179 |  #define dbg(...) 0
      |                   ^
mushrooms.cpp:307:5: note: in expansion of macro 'dbg'
  307 |     dbg("ADDING",ind,i);
      |     ^~~
mushrooms.cpp:179:19: warning: statement has no effect [-Wunused-value]
  179 |  #define dbg(...) 0
      |                   ^
mushrooms.cpp:331:2: note: in expansion of macro 'dbg'
  331 |  dbg("OK",ret);
      |  ^~~
mushrooms.cpp: In function 'void setIn(str)':
mushrooms.cpp:184:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  184 | void setIn(str s) { freopen(s.c_str(),"r",stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
mushrooms.cpp: In function 'void setOut(str)':
mushrooms.cpp:185:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  185 | void setOut(str s) { freopen(s.c_str(),"w",stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100