제출 #1161654

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1161654		pan	Planine (COCI21_planine)	C++20	110 / 110	499 ms	71768 KiB

Main

#include <bits/stdc++.h>
//#include "includeall.h"
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define endl '\n'
#define f first
#define s second
#define pb push_back
#define mp make_pair
#define lb lower_bound
#define ub upper_bound
#define input(x) scanf("%lld", &x);
#define input2(x, y) scanf("%lld%lld", &x, &y);
#define input3(x, y, z) scanf("%lld%lld%lld", &x, &y, &z);
#define input4(x, y, z, a) scanf("%lld%lld%lld%lld", &x, &y, &z, &a);
#define print(x, y) printf("%lld%c", x, y);
#define show(x) cerr << #x << " is " << x << endl;
#define show2(x,y) cerr << #x << " is " << x << " " << #y << " is " << y << endl;
#define show3(x,y,z) cerr << #x << " is " << x << " " << #y << " is " << y << " " << #z << " is " << z << endl;
#define all(x) x.begin(), x.end()
#define discretize(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
#define FOR(i, x, n) for (ll i =x; i<=n; ++i) 
#define RFOR(i, x, n) for (ll i =x; i>=n; --i) 
#pragma GCC optimize("O3","unroll-loops")
using namespace std;
mt19937_64 rnd(chrono::steady_clock::now().time_since_epoch().count());
//using namespace __gnu_pbds;
//#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
//#define ordered_multiset tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update>
typedef long long ll;
typedef long double ld;
typedef pair<ld, ll> pd;
typedef pair<string, ll> psl;
typedef pair<ll, ll> pi;
typedef pair<pi, ll> pii;
typedef pair<pi, pi> piii;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

ll const INF = 1e15;

ll h, n;
pi xy[1000005], l[1000005], r[1000005];
vector<pi> cht;
vector<piii> range;

bool ccw(pi a, pi b, pi c)
{
	return a.f * (b.s - c.s) + b.f * (c.s - a.s) + c.f * (a.s - b.s) > 0;
}

bool compare(piii a, piii b)
{
	return a.s.f*  b.s.s < b.s.f * a.s.s;
}

int main()
{
	cin >> n >> h;
	for (ll i=0; i<n; ++i) cin >> xy[i].f >> xy[i].s;
	cht.clear();
	for (ll i=1; i<n-1; ++i)
	{
		// remove non-convex
		while (cht.size() >= 2 && ccw(cht[cht.size()-2], cht[cht.size()-1], xy[i])) cht.pop_back();
		cht.pb(xy[i]);
		if (i%2==0) // found valley
		{
			pi a1 = cht[cht.size()-1], a2 = cht[cht.size()-2];
			ll dx = (a1.f - a2.f), dy = (a1.s - a2.s);
			l[i] = mp(dx * (h-a2.s) + dy * a2.f  , dy);
		}
	}
	for (ll i=0; i<n; ++i) xy[i].f*=-1;
	cht.clear();
	for (ll i=n-2; i>0; --i)
	{
		// remove non-convex
		while (cht.size() >= 2 && ccw(cht[cht.size()-2], cht[cht.size()-1], xy[i])) cht.pop_back();
		cht.pb(xy[i]);
		if (i%2==0) // found valley
		{
			pi a1 = cht[cht.size()-1], a2 = cht[cht.size()-2];
			ll dx = (a1.f - a2.f), dy = (a1.s - a2.s);
			r[i] = mp(dx * (h-a2.s) + dy * a2.f  , dy);
		}
	}
	for (ll i=0; i<n; ++i) r[i].f *= -1;
	for (ll i=2; i<n; i+=2) range.pb(mp(l[i], r[i]));
	sort(all(range), compare);
	bool fi = 1;
	pi maxx = mp(0, 0);
	ll ans = 0;
	for (piii u: range)
	{
		if (fi || compare(mp(mp(0, 0), maxx), mp(mp(0, 0), u.f))) // fail
		{
			fi = 0;
			maxx = u.s;
			ans++;
		}
	}
	cout << ans << endl;
	return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60