oj.uz

Submission #56674

# Submission time Handle Problem Language Result Execution time Memory
56674 2018-07-12T06:53:31 Z gs14004 Fences (JOI18_fences) C++17
100 / 100
 172 ms 1660 KB 
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 222;
typedef pair<double, double> pi;

double ccw(pi a, pi b, pi c){
	double dx1 = b.first - a.first;
	double dy1 = b.second - a.second;
	double dx2 = c.first - a.first;
	double dy2 = c.second - a.second;
	return dx1 * dy2 - dy1 * dx2;
}

double dot(pi a, pi b, pi c){
	double dx1 = b.first - a.first;
	double dy1 = b.second - a.second;
	double dx2 = c.first - a.first;
	double dy2 = c.second - a.second;
	return dx1 * dx2 + dy1 * dy2;
}

double pdist(pi a, pi b){
	return hypot(a.first - b.first, a.second - b.second);
}

const double eps = 1e-7;
bool line_segment_intersection(pi a, pi b, pi c, pi d){
	double k1 = ccw(a, b, c);
	double k2 = ccw(a, b, d);
	if(k1 > eps && k2 > eps) return false;
	if(k1 < -eps && k2 < -eps) return false;
	k1 = ccw(c, d, a);
	k2 = ccw(c, d, b);
	if(k1 > eps && k2 > eps) return false;
	if(k1 < -eps && k2 < -eps) return false;
	return true;
}

int n, c;
pi a[MAXN];

struct node{
	int pos, arg;
	double dist;
	bool operator<(const node &n)const{
		return dist > n.dist;
	}
};

struct seg{
	double first;
	int second, basecross;
};

vector<seg> gph[MAXN];
double dist[2][MAXN];
bool vis[2][MAXN];

double solve(int p){
	priority_queue<node> pq;
	for(int i=0; i<2; i++){
		for(int j=0; j<2*n+8; j++){
			dist[i][j] = 1e9;
			vis[i][j] = 0;
		}
	}
	dist[0][p] = 0;
	while(true){
		int sx = -1, sy = -1;
		double cur = 1e9;
		for(int i=0; i<2; i++){
			for(int j=0; j<2*n+8; j++){
				if(!vis[i][j] && dist[i][j] < cur){
					cur = dist[i][j];
					sx = i;
					sy = j;
				}
			}
		}
		if(sx == -1 || sy == -1) break;
		vis[sx][sy] = 1;
		for(auto &i : gph[sy]){
			if(dist[sx ^ i.basecross][i.second] > i.first + cur){
				dist[sx ^ i.basecross][i.second] = i.first + cur;
			}
		}
	}
	return dist[1][p];
}

bool is_cross(pi a, pi b){
	return line_segment_intersection(a, b, pi(0, 0), pi(233, 569));
}

void makeGraph(){
	auto add_edge = [&](int s, int e, double x, bool augment = false){
	//	printf("%d %d %.10f\n",s ,e , x);
		gph[s].push_back({x, e, is_cross(a[s], a[e]) ^ augment});
		gph[e].push_back({x, s, is_cross(a[s], a[e]) ^ augment});
	};
	for(int i=0; i<n+4; i++){
		add_edge(2*i, 2*i+1, 0);
	}
	add_edge(2*n, 2*n+2, 2*c);
	add_edge(2*n, 2*n+4, 2*c);
	add_edge(2*n+2, 2*n+6, 2*c);
	add_edge(2*n+4, 2*n+6, 2*c);
	for(int i=0; i<2*n+8; i++){
		for(int j=0; j<2*n; j++){
			if(j % 2 == 1) continue;
			if(i / 2 == j / 2) continue;
			pi p1 = a[i];
			pi p2 = pi(-1, -1);
			if(dot(a[j], a[j+1], p1) < 0 || dot(a[j+1], a[j], p1) < 0){
				if(pdist(a[j], p1) < pdist(a[j+1], p1)) p2 = a[j];
				else p2 = a[j+1];
			}
			else{
				double arg = ccw(a[j], a[j+1], p1) / pdist(a[j], a[j+1]);
				double dx = (a[j+1].first - a[j].first) / pdist(a[j], a[j+1]);
				double dy = (a[j+1].second - a[j].second) / pdist(a[j], a[j+1]);
				p2 = p1;
				p2.first += dy * arg;
				p2.second -= dx * arg;
			}
			if(i == 2 * n || i == 2 * n + 1){
				if(p2.first <= -c || p2.second <= -c) {
					add_edge(i, j, pdist(p1, p2), is_cross(a[i], a[j]) ^ is_cross(p1, p2) ^ is_cross(p2, a[j]));
				}
				else continue;
			}
			if(i == 2 * n + 2 || i == 2 * n + 3){
				if(p2.first <= -c || p2.second >= c){
					add_edge(i, j, pdist(p1, p2), is_cross(a[i], a[j]) ^ is_cross(p1, p2) ^ is_cross(p2, a[j]));
				}
				else continue;
			}
			if(i == 2 * n + 4 || i == 2 * n + 5){
				if(p2.first >= c || p2.second <= -c){
					add_edge(i, j, pdist(p1, p2), is_cross(a[i], a[j]) ^ is_cross(p1, p2) ^ is_cross(p2, a[j]));
				}
				else continue;
			}
			if(i == 2 * n + 6 || i == 2 * n + 7){
				if(p2.first >= c || p2.second >= c){
					add_edge(i, j, pdist(p1, p2), is_cross(a[i], a[j]) ^ is_cross(p1, p2) ^ is_cross(p2, a[j]));
				}
				else continue;
			}
			double lx = -c, rx = c;
			if(line_segment_intersection(p1, p2, pi(lx, rx), pi(lx, lx))) continue;
			if(line_segment_intersection(p1, p2, pi(lx, rx), pi(rx, rx))) continue;
			if(line_segment_intersection(p1, p2, pi(rx, rx), pi(rx, lx))) continue;
			if(line_segment_intersection(p1, p2, pi(rx, lx), pi(lx, lx))) continue;
			add_edge(i, j, pdist(p1, p2), is_cross(a[i], a[j]) ^ is_cross(p1, p2) ^ is_cross(p2, a[j]));
		}
	}
}

int main(){
	cin >> n >> c;
	for(int i=0; i<2*n; i++){
		cin >> a[i].first >> a[i].second;
	}
	a[2*n+0] = a[2*n+1] = pi(-c, -c);
	a[2*n+2] = a[2*n+3] = pi(-c, c);
	a[2*n+4] = a[2*n+5] = pi(c, -c);
	a[2*n+6] = a[2*n+7] = pi(c, c);
	makeGraph();
	double ans = 1e9;
	for(int i=0; i<2*n+8; i++) ans = min(ans, solve(i));
	printf("%.10f\n", ans);
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 3 ms 468 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 2 ms 472 KB Output is correct
5 Correct 2 ms 496 KB Output is correct
6 Correct 3 ms 496 KB Output is correct
7 Correct 2 ms 572 KB Output is correct
8 Correct 2 ms 572 KB Output is correct
9 Correct 2 ms 620 KB Output is correct
10 Correct 2 ms 620 KB Output is correct
11 Correct 2 ms 624 KB Output is correct
12 Correct 2 ms 624 KB Output is correct
13 Correct 3 ms 624 KB Output is correct
14 Correct 2 ms 624 KB Output is correct
15 Correct 2 ms 624 KB Output is correct
16 Correct 2 ms 748 KB Output is correct
17 Correct 2 ms 748 KB Output is correct
18 Correct 2 ms 748 KB Output is correct
19 Correct 3 ms 748 KB Output is correct
20 Correct 2 ms 748 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 3 ms 468 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 2 ms 472 KB Output is correct
5 Correct 2 ms 496 KB Output is correct
6 Correct 3 ms 496 KB Output is correct
7 Correct 2 ms 572 KB Output is correct
8 Correct 2 ms 572 KB Output is correct
9 Correct 2 ms 620 KB Output is correct
10 Correct 2 ms 620 KB Output is correct
11 Correct 2 ms 624 KB Output is correct
12 Correct 2 ms 624 KB Output is correct
13 Correct 3 ms 624 KB Output is correct
14 Correct 2 ms 624 KB Output is correct
15 Correct 2 ms 624 KB Output is correct
16 Correct 2 ms 748 KB Output is correct
17 Correct 2 ms 748 KB Output is correct
18 Correct 2 ms 748 KB Output is correct
19 Correct 3 ms 748 KB Output is correct
20 Correct 2 ms 748 KB Output is correct
21 Correct 2 ms 748 KB Output is correct
22 Correct 2 ms 748 KB Output is correct
23 Correct 3 ms 748 KB Output is correct
24 Correct 2 ms 748 KB Output is correct
25 Correct 2 ms 748 KB Output is correct
26 Correct 3 ms 752 KB Output is correct
27 Correct 3 ms 752 KB Output is correct
28 Correct 2 ms 752 KB Output is correct
29 Correct 0 ms 752 KB Output is correct
30 Correct 2 ms 752 KB Output is correct
31 Correct 3 ms 752 KB Output is correct
32 Correct 3 ms 752 KB Output is correct
33 Correct 2 ms 752 KB Output is correct
34 Correct 2 ms 752 KB Output is correct
35 Correct 2 ms 752 KB Output is correct
36 Correct 4 ms 752 KB Output is correct
37 Correct 2 ms 752 KB Output is correct
38 Correct 2 ms 752 KB Output is correct
39 Correct 2 ms 752 KB Output is correct
40 Correct 2 ms 752 KB Output is correct
41 Correct 2 ms 752 KB Output is correct
42 Correct 3 ms 752 KB Output is correct
43 Correct 2 ms 752 KB Output is correct

Subtask #3
49.0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 3 ms 468 KB Output is correct
3 Correct 2 ms 468 KB Output is correct
4 Correct 2 ms 472 KB Output is correct
5 Correct 2 ms 496 KB Output is correct
6 Correct 3 ms 496 KB Output is correct
7 Correct 2 ms 572 KB Output is correct
8 Correct 2 ms 572 KB Output is correct
9 Correct 2 ms 620 KB Output is correct
10 Correct 2 ms 620 KB Output is correct
11 Correct 2 ms 624 KB Output is correct
12 Correct 2 ms 624 KB Output is correct
13 Correct 3 ms 624 KB Output is correct
14 Correct 2 ms 624 KB Output is correct
15 Correct 2 ms 624 KB Output is correct
16 Correct 2 ms 748 KB Output is correct
17 Correct 2 ms 748 KB Output is correct
18 Correct 2 ms 748 KB Output is correct
19 Correct 3 ms 748 KB Output is correct
20 Correct 2 ms 748 KB Output is correct
21 Correct 2 ms 748 KB Output is correct
22 Correct 2 ms 748 KB Output is correct
23 Correct 3 ms 748 KB Output is correct
24 Correct 2 ms 748 KB Output is correct
25 Correct 2 ms 748 KB Output is correct
26 Correct 3 ms 752 KB Output is correct
27 Correct 3 ms 752 KB Output is correct
28 Correct 2 ms 752 KB Output is correct
29 Correct 0 ms 752 KB Output is correct
30 Correct 2 ms 752 KB Output is correct
31 Correct 3 ms 752 KB Output is correct
32 Correct 3 ms 752 KB Output is correct
33 Correct 2 ms 752 KB Output is correct
34 Correct 2 ms 752 KB Output is correct
35 Correct 2 ms 752 KB Output is correct
36 Correct 4 ms 752 KB Output is correct
37 Correct 2 ms 752 KB Output is correct
38 Correct 2 ms 752 KB Output is correct
39 Correct 2 ms 752 KB Output is correct
40 Correct 2 ms 752 KB Output is correct
41 Correct 2 ms 752 KB Output is correct
42 Correct 3 ms 752 KB Output is correct
43 Correct 2 ms 752 KB Output is correct
44 Correct 138 ms 1660 KB Output is correct
45 Correct 119 ms 1660 KB Output is correct
46 Correct 111 ms 1660 KB Output is correct
47 Correct 113 ms 1660 KB Output is correct
48 Correct 141 ms 1660 KB Output is correct
49 Correct 132 ms 1660 KB Output is correct
50 Correct 128 ms 1660 KB Output is correct
51 Correct 115 ms 1660 KB Output is correct
52 Correct 123 ms 1660 KB Output is correct
53 Correct 127 ms 1660 KB Output is correct
54 Correct 139 ms 1660 KB Output is correct
55 Correct 117 ms 1660 KB Output is correct
56 Correct 127 ms 1660 KB Output is correct
57 Correct 121 ms 1660 KB Output is correct
58 Correct 172 ms 1660 KB Output is correct
59 Correct 131 ms 1660 KB Output is correct
60 Correct 159 ms 1660 KB Output is correct
61 Correct 123 ms 1660 KB Output is correct
62 Correct 2 ms 1660 KB Output is correct
63 Correct 2 ms 1660 KB Output is correct
64 Correct 83 ms 1660 KB Output is correct
65 Correct 83 ms 1660 KB Output is correct
66 Correct 66 ms 1660 KB Output is correct
67 Correct 104 ms 1660 KB Output is correct
68 Correct 105 ms 1660 KB Output is correct
69 Correct 137 ms 1660 KB Output is correct
70 Correct 133 ms 1660 KB Output is correct
71 Correct 114 ms 1660 KB Output is correct
72 Correct 121 ms 1660 KB Output is correct