Submission #241860

#	Time	Username	Problem	Language	Result	Execution time	Memory
241860		rqi	Aliens (IOI16_aliens)	C++14	100 / 100	276 ms	9064 KiB

aliens

#include "aliens.h"
#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef double db; 
typedef string str; 

typedef pair<int,int> pi;
typedef pair<ll,ll> pl; 
typedef pair<db,db> pd; 

typedef vector<int> vi; 
typedef vector<ll> vl; 
typedef vector<db> vd; 
typedef vector<str> vs; 
typedef vector<pi> vpi;
typedef vector<pl> vpl; 
typedef vector<pd> vpd; 

#define mp make_pair
#define f first
#define s second
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() 
#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 

#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; 
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1}; 
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); 

template<class T> bool ckmin(T& a, const T& b) { 
	return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { 
	return a < b ? a = b, 1 : 0; } 
int pct(int x) { return __builtin_popcount(x); } 
int bits(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) 
int cdiv(int a, int b) { return a/b+!(a<0||a%b == 0); } // division of a by b rounded up, assumes b > 0 
int fstTrue(function<bool(int)> f, int lo, int hi) {
	hi ++; assert(lo <= hi); // assuming f is increasing
	while (lo < hi) { // find first index such that f is true 
		int mid = (lo+hi)/2; 
		f(mid) ? hi = mid : lo = mid+1; 
	} 
	return lo;
}

// INPUT
template<class A> void re(complex<A>& c);
template<class A, class B> void re(pair<A,B>& p);
template<class A> void re(vector<A>& v);
template<class A, size_t SZ> void re(array<A,SZ>& a);

template<class T> 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); }
template<class H, class... T> void re(H& h, T&... t) { re(h); re(t...); }

template<class A> void re(complex<A>& c) { A a,b; re(a,b); c = {a,b}; }
template<class A, class B> void re(pair<A,B>& p) { re(p.f,p.s); }
template<class A> void re(vector<A>& x) { trav(a,x) re(a); }
template<class A, size_t SZ> void re(array<A,SZ>& x) { trav(a,x) re(a); }

// TO_STRING
#define ts to_string
str ts(char c) { return str(1,c); }
str ts(bool b) { return b ? "true" : "false"; }
str ts(const char* s) { return (str)s; }
str ts(str s) { return s; }
template<class A> str ts(complex<A> 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; }
template<class A, class B> str ts(pair<A,B> p);
template<class T> str ts(T v) { // containers with begin(), end()
	bool fst = 1; str res = "{";
	for (const auto& x: v) {
		if (!fst) res += ", ";
		fst = 0; res += ts(x);
	}
	res += "}"; return res;
}
template<class A, class B> str ts(pair<A,B> p) {
	return "("+ts(p.f)+", "+ts(p.s)+")"; }

// OUTPUT
template<class A> void pr(A x) { cout << ts(x); }
template<class H, class... T> void pr(const H& h, const T&... t) { 
	pr(h); pr(t...); }
void ps() { pr("\n"); } // print w/ spaces
template<class H, class... T> void ps(const H& h, const T&... t) { 
	pr(h); if (sizeof...(t)) pr(" "); ps(t...); }

// DEBUG
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) {
	cerr << ts(h); if (sizeof...(t)) cerr << ", ";
	DBG(t...); }
#ifdef LOCAL // compile with -DLOCAL
#define dbg(...) cerr << "LINE(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 0
#endif

// FILE I/O
void setIn(string s) { freopen(s.c_str(),"r",stdin); }
void setOut(string s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { ios_base::sync_with_stdio(0); cin.tie(0); }
void setIO(string 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
}

/**
 * Description: LineContainer; add lines of the form $kx+m$, 
 	* compute greatest $y$-coordinate for any $x$.
 * Time: O(\log N)
 * Source: KACTL
   * https://github.com/kth-competitive-programming/kactl/commit/165807e28402c9be906f6e6a09452431787bb70d?diff=unified
 * Verification: 
   * CSA Squared Ends not working :(
   * https://codeforces.com/contest/1083/problem/E
   * https://atcoder.jp/contests/arc066/tasks/arc066_d
 */

bool Q;
struct Line {
	mutable ll k, m, p, lnum; // slope, y-intercept, last optimal x, LAMBDAS used
	pair<ll, int> eval (ll x) { return mp(k*x+m, lnum); }
	bool operator<(const Line& o) const { return Q?p<o.p:k<o.k; }
};

// for doubles, use inf = 1/.0, divi(a,b) = a/b
const ll inf = LLONG_MAX;
// floored div
ll divi(ll a, ll b) { return a/b-((a^b) < 0 && a%b); } 
// last x such that first line is better
ll bet(const Line& x, const Line& y) { 
	if (x.k == y.k){
		if(x.m > y.m) return inf;
		if(x.m < y.m) return -inf;
		if(x.lnum <= y.lnum) return inf;
		return -inf;
	}
	if((y.m-x.m) % (x.k-y.k) == 0){
		if(x.lnum <= y.lnum){
			return (y.m-x.m)/(x.k-y.k)-1;
		}
		return (y.m-x.m)/(x.k-y.k);
	}
	return divi(y.m-x.m,x.k-y.k); }




/**
 * Description: LineContainer assuming both slopes and queries monotonic.
 * Time: O(1)
 * Source: Own
 * Verification: http://acm.hdu.edu.cn/diy/contest_showproblem.php?cid=36005&pid=1009
 */

struct LCdeque : deque<Line> { 
	void addBack(Line L) { // assume nonempty
		while (1) {
			auto a = bk; pop_back(); a.p = bet(a,L);
			if (size() && bk.p >= a.p) continue;
			pb(a); break;
		}
		L.p = inf; pb(L);
	}
	void addFront(Line L) {
		while (1) {
			if (!size()) { L.p = inf; break; }
			if ((L.p = bet(L,ft)) >= ft.p) pop_front();
			else break;
		}
		push_front(L);
	}
	void add(ll k, ll m, ll lnum) { // line goes to one end of deque
		k = -k;
		m = -m;
		lnum = -lnum;
		if (!size() || k <= ft.k) addFront({k,m,0,lnum});
		else assert(k >= bk.k), addBack({k,m,0,lnum});
	}
	int ord = 1; // 1 = increasing, -1 = decreasing
	pair<ll, int> query(ll x) { 
		assert(ord);
		pair<ll, int> rval;
		if (ord == 1) { 
			while (ft.p < x) pop_front();
			rval = ft.eval(x);
		} else {
			while(size()>1&&prev(prev(end()))->p>=x)pop_back();
			rval = bk.eval(x);
		}
		rval.f = -rval.f;
		rval.s = -rval.s;
		return rval;
	}	
};



vpl points;
pair<ll, int> dp[100005];
LCdeque lins;

pair<ll, int> testLambda(ll lamb){
	//clear memory
	for(int i = 0; i < sz(points); i++){
		dp[i] = mp(INF, -1);
	}
	lins.clear();

	lins.add(2*(-points[0].f+1), (-points[0].f+1)*(-points[0].f+1)+lamb, 1);
	for(int i = 0; i < sz(points); i++){
		//query to get dp[i]
		dp[i] = lins.query(points[i].s);
		dp[i].f+=ll(points[i].s)*points[i].s;
		//add to deque if it's not sz(points)-1
		if(i == sz(points)-1) break;
		if(points[i].s < points[i+1].f){
			lins.add(2*(-points[i+1].f+1), dp[i].f+(-points[i+1].f+1)*(-points[i+1].f+1)+lamb, dp[i].s+1);
		}
		else{
			lins.add(2*(-points[i+1].f+1), dp[i].f+(-points[i+1].f+1)*(-points[i+1].f+1)-(points[i].s-points[i+1].f+1)*(points[i].s-points[i+1].f+1)+lamb, dp[i].s+1);
		}
	}
	//ps(lamb, dp[sz(points)-1]);
	return dp[sz(points)-1];
}

ll take_photos(int n, int m, int k, vi r, vi c) {
	for(int i = 0; i < n; i++){
		if(r[i] > c[i]) swap(r[i], c[i]);
	}
	vector<pair<pi, int>> sortorig;
	for(int i = 0; i < n; i++){
		sortorig.pb(mp(mp(r[i], c[i]), i));
	}
	sort(all(sortorig));
	//ps(sortorig);
	int curr = -1;
	for(int i = 0; i < sz(sortorig); i++){
		pair<pi, int> u = sortorig[i];
		if(i+1 < sz(sortorig) && sortorig[i].f.f == sortorig[i+1].f.f) continue;
		if(u.f.s <= curr) continue;
		curr = u.f.s;
		points.pb(mp(u.f.f, u.f.s));
	}

	//ps(points);

	ll lo = 0;
	ll hi = 1000000000005LL;
	while(lo < hi){
		ll mid = (lo+hi)/2;
		pair<ll, int> tans = testLambda(mid);
		if(tans.s <= k){
			hi = mid;
		}
		else{
			lo = mid+1;
		}
	}

	pair<ll, int> fans = testLambda(lo);
	ll ans = fans.f;
	ans-=lo*ll(k);

    return ans;
}

Compilation message (stderr)

aliens.cpp: In function 'void setIn(std::__cxx11::string)':
aliens.cpp:129:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
 void setIn(string s) { freopen(s.c_str(),"r",stdin); }
                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
aliens.cpp: In function 'void setOut(std::__cxx11::string)':
aliens.cpp:130:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
 void setOut(string s) { freopen(s.c_str(),"w",stdout); }
                         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 12 / 12
• Subtask 3: 9 / 9
• Subtask 4: 16 / 16
• Subtask 5: 19 / 19
• Subtask 6: 40 / 40