Submission #51518

#	Time	Username	Problem	Language	Result	Execution time	Memory
51518		spencercompton	Bulldozer (JOI17_bulldozer)	C++17	5 / 100	31 ms	396 KiB

bulldozer

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
double ptLineDist(double x1, double y1, double x2, double y2, double px, double py){
	double pd2 = (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
	double x, y;
	if(pd2 == 0){
		x = x1;
		y = y2;
	}
	else{
		double u = ((px-x1) * (x2 - x1) + (py - y1) * (y2-y1)) / pd2;
		x = x1 + u * (x2 - x1);
		y = y1 + u * (y2 - y1);
	}
	return (x-px) * (x - px) + (y - py) * (y - py);
}

int main(){
	int n;
	cin >> n;
	ll ans = 0LL;
	ll x[n];
	ll y[n];
	ll v[n];
	for(int i = 0; i<n; i++){
		cin >> x[i] >> y[i] >> v[i];
	}
	for(int i = 0; i<n; i++){
		ans = max(ans,v[i]);
		for(int j = i+1; j<n; j++){
			ll dx = x[j]-x[i];
			ll dy = y[j]-y[i];
			//(dy,-dx);
			vector<pair<double, ll> > li;
			for(int k = 0; k<n; k++){
				bool cross = (y[k]+dx)*(dy-0LL) > (-dx-0LL)*(x[k]-dy);
				double dist = ptLineDist(0LL, 0LL, dy, -dx, x[k], y[k]);
				if(cross){
					li.push_back(make_pair(dist,v[k]));
				}
				else{
					li.push_back(make_pair(-dist,v[k]));
				}
			}
			sort(li.begin(),li.end());
			ll bestPre = 0LL;
			ll cur = 0LL;
			double tol = -1;
			for(int k = 0; k<n; k++){
				if(k>0 && li[k].first-li[k-1].first>tol){
					bestPre = min(bestPre,cur);
				}
				cur += li[k].second;
				if(k==n-1 || li[k+1].first-li[k].first>tol){
					ans = max(ans,cur-bestPre);
				}
			}
		}
	}

	// for(int i = 0; i<n; i++){
	// 	ans = max(ans,v[i]);
	// 	for(int j = i+1; j<n; j++){
	// 		ans = max(ans,v[i]+v[j]);
	// 		ll dx = x[j]-x[i];
	// 		ll dy = y[j]-y[i];
	// 		swap(dx,dy);
	// 		dx = -dx;
	// 		//(dy,-dx);
	// 		vector<pair<double, ll> > li;
	// 		for(int k = 0; k<n; k++){
	// 			bool cross = (y[k]+dx)*(dy-0LL) > (-dx-0LL)*(x[k]-dy);
	// 			double dist = ptLineDist(0LL, 0LL, dy, -dx, x[k], y[k]);
	// 			if(cross){
	// 				li.push_back(make_pair(dist,v[k]));
	// 			}
	// 			else{
	// 				li.push_back(make_pair(-dist,v[k]));
	// 			}
	// 		}
	// 		sort(li.begin(),li.end());
	// 		ll bestPre = 0LL;
	// 		ll cur = 0LL;
	// 		double tol = -1;
	// 		for(int k = 0; k<n; k++){
	// 			if(k>0 && li[k].first-li[k-1].first>tol){
	// 				bestPre = min(bestPre,cur);
	// 			}
	// 			cur += li[k].second;
	// 			if(k==n-1 || li[k+1].first-li[k].first>tol){
	// 				ans = max(ans,cur-bestPre);
	// 			}
	// 		}
	// 	}
	// }
	cout << ans << endl;
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 20
• Subtask 3: 0 / 35
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20