Submission #104948

#	Time	Username	Problem	Language	Result	Execution time	Memory
104948		Shtef	SIR (COI15_sir)	C++14	51 / 100	1062 ms	17720 KiB

sir

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

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];

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;
}

bool jedobar(pll x, pll y, int kolko){
	for(int i = 0 ; i < m ; ++i){
		if(ccw(x, y, b[i]) != kolko)
			return 0;
	}
	return 1;
}

ll povrsina(vector <pll> pts){
	if((int)pts.size() < 3)
		return 0LL;
	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;
}
int l = 1, r = 1;
ll sol = 0;
for(int i = 0 ; i < n ; ++i){
	if(i == l)
		l++;
	if(i == r)
		r++;
	while(!jedobar(a[i], a[l], -1)){
		l = (l + 1) % n;
	}
	while(jedobar(a[i], a[r], 1)){
		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]);
		//cout << j << ' ';
	}
	v.push_back(a[i]);
	sol = max(sol, povrsina(v));
	//cout << i << " : : : " << sol << " - ";
	v.clear();
	for(int j = i ; j != r ; j = (j + 1) % n){
		v.push_back(a[j]);
		//cout << j << ' ';
	}
	v.push_back(a[r]);
	//cout << r << endl;
	sol = max(sol, povrsina(v));
	v.clear();
	//cout << sol << endl;
	//cout << i << "-" << l << " : " << r << endl;
}
cout << sol << endl;

return 0;
}

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