Submission #405001

#	Time	Username	Problem	Language	Result	Execution time	Memory
405001		Benq	Circle selection (APIO18_circle_selection)	C++17	37 / 100	3080 ms	243688 KiB

circle_selection

#include <bits/stdc++.h>
using namespace std;
 
using ll = long long;
using db = long double; // or double, if TL is tight
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
#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>; 
tcT> using PR = pair<T,T>;

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

// 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 ft front()
#define bk back()
#define pb push_back
#define eb emplace_back 
#define pf push_front
#define rtn return

#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 lwb_ok(V<T>& a, const T& b) { 
	int x = lwb(a,b);
	assert(a.at(x) == b); 
	return x;
}

// 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 = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INF = 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; }

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(it); } // element that doesn't exist from (multi)set

#define tcTUU tcT, class ...U

inline namespace Helpers {
	//////////// is_iterable
	// https://stackoverflow.com/questions/13830158/check-if-a-variable-type-is-iterable
	// this gets used only when we can call begin() and end() on that type
	tcT, class = void> struct is_iterable : false_type {};
	tcT> struct is_iterable<T, void_t<decltype(begin(declval<T>())),
	                                  decltype(end(declval<T>()))
	                                 >
	                       > : true_type {};
	tcT> constexpr bool is_iterable_v = is_iterable<T>::value;

	//////////// is_readable
	tcT, class = void> struct is_readable : false_type {};
	tcT> struct is_readable<T,
	        typename std::enable_if_t<
	            is_same_v<decltype(cin >> declval<T&>()), istream&>
	        >
	    > : true_type {};
	tcT> constexpr bool is_readable_v = is_readable<T>::value;

	//////////// is_printable
	// // https://nafe.es/posts/2020-02-29-is-printable/
	tcT, class = void> struct is_printable : false_type {};
	tcT> struct is_printable<T,
	        typename std::enable_if_t<
	            is_same_v<decltype(cout << declval<T>()), ostream&>
	        >
	    > : true_type {};
	tcT> constexpr bool is_printable_v = is_printable<T>::value;
}

inline namespace Input {
	tcT> constexpr bool needs_input_v = !is_readable_v<T> && is_iterable_v<T>;
	tcTUU> void re(T& t, U&... u);
	tcTU> void re(pair<T,U>& p); // pairs

	// re: read
	tcT> typename enable_if<is_readable_v<T>,void>::type re(T& x) { cin >> x; } // default
	tcT> void re(complex<T>& c) { T a,b; re(a,b); c = {a,b}; } // complex
	tcT> typename enable_if<needs_input_v<T>,void>::type re(T& i); // ex. vectors, arrays
	tcTU> void re(pair<T,U>& p) { re(p.f,p.s); }
	tcT> typename enable_if<needs_input_v<T>,void>::type re(T& i) {
		each(x,i) re(x); }
	tcTUU> void re(T& t, U&... u) { re(t); re(u...); } // read multiple

	// rv: resize and read vectors
	void rv(size_t) {}
	tcTUU> void rv(size_t N, V<T>& t, U&... u);
	template<class...U> void rv(size_t, size_t N2, U&... u);
	tcTUU> void rv(size_t N, V<T>& t, U&... u) {
		t.rsz(N); re(t);
		rv(N,u...); }
	template<class...U> void rv(size_t, size_t N2, U&... u) {
		rv(N2,u...); }

	// dumb shortcuts to read in ints
	void decrement() {} // subtract one from each
	tcTUU> void decrement(T& t, U&... u) { --t; decrement(u...); }
	#define ints(...) int __VA_ARGS__; re(__VA_ARGS__);
	#define int1(...) ints(__VA_ARGS__); decrement(__VA_ARGS__);
}

inline namespace ToString {
	tcT> constexpr bool needs_output_v = !is_printable_v<T> && is_iterable_v<T>;

	// ts: string representation to print
	tcT> typename enable_if<is_printable_v<T>,str>::type ts(T v) {
		stringstream ss; ss << fixed << setprecision(15) << v;
		return ss.str(); } // default
	tcT> str bit_vec(T t) { // bit vector to string
		str res = "{"; F0R(i,sz(t)) res += ts(t[i]);
		res += "}"; return res; }
	str ts(V<bool> v) { return bit_vec(v); }
	template<size_t SZ> str ts(bitset<SZ> b) { return bit_vec(b); } // bit vector
	tcTU> str ts(pair<T,U> p); // pairs
	tcT> typename enable_if<needs_output_v<T>,str>::type ts(T v); // vectors, arrays
	tcTU> str ts(pair<T,U> p) { return "("+ts(p.f)+", "+ts(p.s)+")"; }
	tcT> typename enable_if<is_iterable_v<T>,str>::type ts_sep(T v, str sep) {
		// convert container to string w/ separator sep
		bool fst = 1; str res = "";
		for (const auto& x: v) {
			if (!fst) res += sep;
			fst = 0; res += ts(x);
		}
		return res;
	}
	tcT> typename enable_if<needs_output_v<T>,str>::type ts(T v) {
		return "{"+ts_sep(v,", ")+"}"; }

	// for nested DS
	template<int, class T> typename enable_if<!needs_output_v<T>,vs>::type 
	  ts_lev(const T& v) { return {ts(v)}; }
	template<int lev, class T> typename enable_if<needs_output_v<T>,vs>::type 
	  ts_lev(const T& v) {
		if (lev == 0 || !sz(v)) return {ts(v)};
		vs res;
		for (const auto& t: v) {
			if (sz(res)) res.bk += ",";
			vs tmp = ts_lev<lev-1>(t);
			res.ins(end(res),all(tmp));
		}
		F0R(i,sz(res)) {
			str bef = " "; if (i == 0) bef = "{";
			res[i] = bef+res[i];
		}
		res.bk += "}";
		return res;
	}
}

inline namespace Output {
	template<class T> void pr_sep(ostream& os, str, const T& t) { os << ts(t); }
	template<class T, class... U> void pr_sep(ostream& os, str sep, const T& t, const U&... u) {
		pr_sep(os,sep,t); os << sep; pr_sep(os,sep,u...); }
	// print w/ no spaces
	template<class ...T> void pr(const T&... t) { pr_sep(cout,"",t...); } 
	// print w/ spaces, end with newline
	void ps() { cout << "\n"; }
	template<class ...T> void ps(const T&... t) { pr_sep(cout," ",t...); ps(); } 
	// debug to cerr
	template<class ...T> void dbg_out(const T&... t) {
		pr_sep(cerr," | ",t...); cerr << endl; }
	void loc_info(int line, str names) {
		cerr << "Line(" << line << ") -> [" << names << "]: "; }
	template<int lev, class T> void dbgl_out(const T& t) {
		cerr << "\n\n" << ts_sep(ts_lev<lev>(t),"\n") << "\n" << endl; }
	#ifdef LOCAL
		#define dbg(...) loc_info(__LINE__,#__VA_ARGS__), dbg_out(__VA_ARGS__)
		#define dbgl(lev,x) loc_info(__LINE__,#x), dbgl_out<lev>(x)
	#else // don't actually submit with this
		#define dbg(...) 0
		#define dbgl(lev,x) 0
	#endif
}

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
		// 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
	}
}

using P = pi;
int N;
V<pair<P,int>> circ;

struct Data {
	int xl,xr,yl,yr;
	friend str ts(const Data& d) {
		return ts(vi{d.xl,d.xr,d.yl,d.yr});
	}
};

V<Data> compress;
vi X,Y;

ll sq(ll x) { return x*x; }
ll norm(P p) { return sq(p.f)+sq(p.s); }

P operator-(P a, P b) { return {a.f-b.f,a.s-b.s}; }
bool isect(int x, int y) {
	return norm(circ[x].f-circ[y].f) <= sq(circ[x].s+circ[y].s);
}

int smaller_ind(int x, int y) {
	if (x == -1) return y;
	if (y == -1) return x;
	if (circ[x].s != circ[y].s) {
		if (circ[x].s > circ[y].s) return x;
		return y;
	}
	return min(x,y);
}

const int BIG = 2e7;
int pre[BIG], val[BIG], cnt;

int list_add(int p, int v) {
	int label = ++cnt; assert(label < BIG);
	pre[label] = p;
	val[label] = v;
	return label;
}

struct Seg {
	int N;
	AR<vi,1<<21> ys,ans;
	void init(int _N) {
		N = _N;
		int n = 1; while (n < N) n *= 2;
		n *= 2;
	}
	int lookup(int cind, pi p, int ind, int L, int R) {
		int res = -1;
		int pos = lwb(ys[ind],p.s);
		if (pos < sz(ys[ind])) 
			for (int j = ans[ind][pos]; j; j = pre[j]) {
				int v = val[j];
				if (isect(cind,v))
					res = smaller_ind(res,v);
			}
		if (L != R) {
			int M = (L+R)/2;
			if (p.f <= M) res = smaller_ind(res,lookup(cind,p,2*ind,L,M));
			else res = smaller_ind(res,lookup(cind,p,2*ind+1,M+1,R));
		}
		return res;
	}
	int lookup(int cind, pi p) {
		return lookup(cind,p,1,0,N-1);
	}
	void add_seg_pre(int lo, int hi, int y, int ind, int L, int R) {
		if (hi < L || R < lo) return;
		if (lo <= L && R <= hi) {
			if (sz(ys[ind]) && ys[ind].bk == y) return;
			ys[ind].pb(y);
			return;
		}
		int M = (L+R)/2;
		add_seg_pre(lo,hi,y,2*ind,L,M);
		add_seg_pre(lo,hi,y,2*ind+1,M+1,R);
	}
	void add_seg_pre(pi l, int y) { add_seg_pre(l.f,l.s,y,1,0,N-1); }
	void add_seg(int lo, int hi, pi y, int label, int ind, int L, int R) {
		if (hi < L || R < lo) return;
		if (lo <= L && R <= hi) {
			// dbg("??",ys[ind],y);
			int a = lwb_ok(ys[ind],y.f);
			while (a < sz(ys[ind]) && ys[ind][a] <= y.s) {
				ans[ind][a] = list_add(ans[ind][a],label);
				++a;
			}
			// int b = lwb_ok(ys[ind],y.s);
			// FOR(i,a,b+1) ans[ind][i] = list_add(ans[ind][i],label);
			return;
		}
		int M = (L+R)/2;
		add_seg(lo,hi,y,label,2*ind,L,M);
		add_seg(lo,hi,y,label,2*ind+1,M+1,R);
	}
	void add_seg(pi l, pi r, int label) { add_seg(l.f,l.s,r,label,1,0,N-1); }
	void gen() {
		F0R(i,sz(ys)) {
			// remDup(ys[i]);
			// assert(is_sorted(all(ys[i])));
			ans[i].rsz(sz(ys[i]));
		}
	}
} seg;

int lookup_isect(int ind) {
	int res = -1;
	int a = seg.lookup(ind,{compress[ind].xl,compress[ind].yl});
	int b = seg.lookup(ind,{compress[ind].xr,compress[ind].yl});
	int c = seg.lookup(ind,{compress[ind].xl,compress[ind].yr});
	int d = seg.lookup(ind,{compress[ind].xr,compress[ind].yr});
	res = smaller_ind(res,a);
	res = smaller_ind(res,b);
	res = smaller_ind(res,c);
	res = smaller_ind(res,d);
	return res;
}	

// void add_seg_pre(int ind) {
// 	seg.add_seg_pre({compress[ind].xl,compress[ind].xr},{compress[ind].yl,compress[ind].yr});
// }

void add_seg(int ind) {
	seg.add_seg({compress[ind].xl,compress[ind].xr},{compress[ind].yl,compress[ind].yr},ind);
}

clock_t beg = clock();

int main() {
	setIO(); re(N);
	circ.rsz(N); 
	each(t,circ) {
		t.f = {rng()%1000000000,0};
		t.s = rng()%1000000+1;
	}
	re(circ);
	each(t,circ) {
		X.pb(t.f.f-t.s);
		X.pb(t.f.f+t.s);
		Y.pb(t.f.s-t.s);
		Y.pb(t.f.s+t.s);
	}
	remDup(X);
	remDup(Y);
	dbg((db)(clock()-beg)/CLOCKS_PER_SEC);
	each(t,circ) {
		compress.pb(Data{lwb_ok(X,t.f.f-t.s),
			lwb_ok(X,t.f.f+t.s),
			lwb_ok(Y,t.f.s-t.s),
			lwb_ok(Y,t.f.s+t.s)});
	}
	vi inds(N); iota(all(inds),0);
	sort(all(inds),[&](int x, int y) {
		return smaller_ind(x,y) == x;
	});
	dbg("DONE INIT");
	seg.init(sz(X));
	{
		vpi res;
		F0R(i,N) {
			res.pb({compress[i].yl,i});
			res.pb({compress[i].yr,i});
		}
		sort(all(res));
		each(t,res) {
			seg.add_seg_pre(mp(compress[t.s].xl,compress[t.s].xr),t.f);
		}
	}
	// F0R(i,N) add_seg_pre(i);
	seg.gen();
	dbg((db)(clock()-beg)/CLOCKS_PER_SEC);
	dbg("DONE GEN SEG");
	// dbg(inds);
	// each(t,inds) dbg(t,compress[t]);
	vi ans(N,-1);
	each(t,inds) {
		// dbg("LOOKING UP");
		int res = lookup_isect(t);
		if (res == -1) {
			res = t;
		// dbg("ADDING");
			add_seg(t);
		}
		ans[t] = res;
	}
	dbg((db)(clock()-beg)/CLOCKS_PER_SEC);
	// #ifndef LOCAL
		each(t,ans) cout << t+1 << ' ';
	// #endif
	// you should actually read the stuff at the bottom
}

/* stuff you should look for
	* int overflow, array bounds
	* special cases (n=1?)
	* do smth instead of nothing and stay organized
	* WRITE STUFF DOWN
	* DON'T GET STUCK ON ONE APPROACH
*/

Compilation message (stderr)

circle_selection.cpp: In function 'int main()':
circle_selection.cpp:244:20: warning: statement has no effect [-Wunused-value]
  244 |   #define dbg(...) 0
      |                    ^
circle_selection.cpp:408:2: note: in expansion of macro 'dbg'
  408 |  dbg((db)(clock()-beg)/CLOCKS_PER_SEC);
      |  ^~~
circle_selection.cpp:244:20: warning: statement has no effect [-Wunused-value]
  244 |   #define dbg(...) 0
      |                    ^
circle_selection.cpp:419:2: note: in expansion of macro 'dbg'
  419 |  dbg("DONE INIT");
      |  ^~~
circle_selection.cpp:244:20: warning: statement has no effect [-Wunused-value]
  244 |   #define dbg(...) 0
      |                    ^
circle_selection.cpp:434:2: note: in expansion of macro 'dbg'
  434 |  dbg((db)(clock()-beg)/CLOCKS_PER_SEC);
      |  ^~~
circle_selection.cpp:244:20: warning: statement has no effect [-Wunused-value]
  244 |   #define dbg(...) 0
      |                    ^
circle_selection.cpp:435:2: note: in expansion of macro 'dbg'
  435 |  dbg("DONE GEN SEG");
      |  ^~~
circle_selection.cpp:244:20: warning: statement has no effect [-Wunused-value]
  244 |   #define dbg(...) 0
      |                    ^
circle_selection.cpp:449:2: note: in expansion of macro 'dbg'
  449 |  dbg((db)(clock()-beg)/CLOCKS_PER_SEC);
      |  ^~~
circle_selection.cpp: In function 'void FileIO::setIn(str)':
circle_selection.cpp:250:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  250 |  void setIn(str s)  { freopen(s.c_str(),"r",stdin); }
      |                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
circle_selection.cpp: In function 'void FileIO::setOut(str)':
circle_selection.cpp:251:30: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  251 |  void setOut(str s) { freopen(s.c_str(),"w",stdout); }
      |                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 0 / 12
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 30 / 30
• Subtask 6: 0 / 13