Submission #105087

#	Time	Username	Problem	Language	Result	Execution time	Memory
105087		Shtef	SIR (COI15_sir)	C++14	0 / 100	1057 ms	14684 KiB

sir

#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>

using namespace std;

typedef long long ll;
typedef pair <ll, ll> pll;
#define x first
#define y second
#define mp make_pair

int n, m;
pll a[300005], b[300005];
vector <pll> gore, dolje, h;

int ccw(pll x, pll y, pll z){
	ll ret = x.x * (y.y - z.y) + y.x * (z.y - x.y) + z.x * (x.y - y.y);
	if(ret > 0)
		return 1;
	if(ret < 0)
		return -1;
	return 0;
}

void initconvexhull(){
	sort(b, b + m);
	gore.push_back(b[0]);
	dolje.push_back(b[0]);
	for(int i = 1 ; i < m ; ++i){
		if(i == m - 1 || ccw(b[0], b[i], b[m - 1]) < 0){
			while((int)gore.size() >= 2 && ccw(gore[(int)gore.size() - 2], gore.back(), b[i]) > 0){
				gore.pop_back();
			}
			gore.push_back(b[i]);
		}
	}
	for(int i = 1 ; i < m ; ++i){
		if(i == m - 1 || ccw(b[0], b[i], b[m - 1]) > 0){
			while((int)dolje.size() >= 2 && ccw(dolje[(int)dolje.size() - 2], dolje.back(), b[i]) < 0){
				dolje.pop_back();
			}
			dolje.push_back(b[i]);
		}
	}
	for(int i = 0 ; i < (int)dolje.size() ; ++i){
		h.push_back(dolje[i]);
	}
	for(int i = (int)gore.size() - 2 ; i > 0 ; --i){
		h.push_back(gore[i]);
	}
}

ll povrsina(vector <pll> pts){
	ll ret = 0;
	for(int i = 0 ; i < (int)pts.size() ; ++i){
		ret += (pts[i].x * pts[(i + 1) % ((int)pts.size())].y - pts[(i + 1) % ((int)pts.size())].x * pts[i].y);
	}
	return ret;
}

int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n;
for(int i = 0 ; i < n ; ++i){
	cin >> a[i].x >> a[i].y;
}
cin >> m;
for(int i = 0 ; i < m ; ++i){
	cin >> b[i].x >> b[i].y;
}
initconvexhull();
m = (int)h.size();
int l = 1, r = 1;
int hl = (int)dolje.size() - 1, hr = 0;
ll sol = 0;
for(int i = 0 ; i < n ; ++i){
	while(ccw(a[i], h[hl], h[(hl + 1) % m]) > 0){
		hl = (hl + 1) % m;
	}
	while(ccw(a[i], h[hr], h[(hr + 1) % m]) < 0){
		hr = (hr + 1) % n;
	}
	if(i == l)
		l = (l + 1) % n;
	if(i == r)
		r = (r + 1) % n;
	while(ccw(a[i], h[hl], a[l]) <= 0){
		l = (l + 1) % n;
	}
	while(ccw(a[i], h[hr], a[r]) < 0){
		r = (r + 1) % n;
	}
	r = (r - 1 + n) % n;
	vector <pll> v;
	for(int j = l ; j != i ; j = (j + 1) % n){
		v.push_back(a[j]);
	}
	v.push_back(a[i]);
	sol = max(sol, povrsina(v));
	v.clear();
	for(int j = i ; j != r ; j = (j + 1) % n){
		v.push_back(a[j]);
	}
	v.push_back(a[r]);
	sol = max(sol, povrsina(v));
	v.clear();
}
cout << sol << endl;

return 0;
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 39
• Subtask 3: 0 / 49