oj.uz

Submission #132035

# Submission time Handle Problem Language Result Execution time Memory
132035 2019-07-18T08:28:21 Z 이온조(#3189) Fences (JOI18_fences) C++14
51 / 100
 1000 ms 241920 KB 
#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
using pid = pair<int, double>;
using pdi = pair<double, int>;
using pdd = pair<double, double>;
#define X first
#define Y second

const double eps = 1e-6;

struct line { pdd S, E; };
struct dot { pdd D; int id; bool ps; };
struct node { double v; int c, id; };

bool operator <(node PP, node QQ) { return PP.v > QQ.v; }

inline double f(double x) { return max(x, -x); }
inline double dst(pdd A, pdd B) { return sqrt((A.X-B.X) * (A.X-B.X) + (A.Y-B.Y) * (A.Y-B.Y)); }
inline double CCW(pdd A, pdd B, pdd C) { return A.X*B.Y + B.X*C.Y + C.X*A.Y - A.Y*B.X - B.Y*C.X - C.Y*A.X; }
inline int CCWs(pdd A, pdd B, pdd C) {
	double tmp = CCW(A, B, C);
	if(f(tmp) < eps) return 0;
	if(tmp < 0) return -1;
	if(tmp > 0) return +1;
}
inline bool on(line A, pdd B) {
	if(A.S > A.E) swap(A.S, A.E);
	if(B < A.S || A.E < B) return false;
	return f(CCW(A.S, A.E, B)) < eps;
}
inline bool its(line A, line B) { // strict
	return CCWs(A.S, A.E, B.S) * CCWs(A.S, A.E, B.E) == -1 && CCWs(B.S, B.E, A.S) * CCWs(B.S, B.E, A.E) == -1;
}
inline pdd push(line A, pdd B) {
	double ds = dst(A.S, A.E);
	double d = f(CCW(A.S, A.E, B) / ds);
	double dx = A.S.Y - A.E.Y, dy = A.E.X - A.S.X;
	pdd PA = {B.X + dx * (d/ds), B.Y + dy * (d/ds)};
	pdd PB = {B.X - dx * (d/ds), B.Y - dy * (d/ds)};
	if(dst(PA, A.S) > dst(PB, A.S)) swap(PA, PB);
	return PA;
}

line I = {{0.0, 0.0}, {1000.0, 1.0}};
vector<dot> T;
vector<pid> adj[1000009];
line A[111];
int N, S, K;
double ans = 1e9, D[2][1000009];
bool IT[40009][40009];

inline bool ok(line L) {
	bool f = 0;
	f |= its(L, {{S, S}, {-S, -S}});
	f |= its(L, {{-S, S}, {S, -S}});
	return !f;
}

void dijk(int st) {
	// printf("start: (%d, %d)\n", T[st].D.X, T[st].D.Y);
	vector<pii> rec = {{0, st}};
	D[0][st] = 0.0;
	priority_queue<node> pq; pq.push({0.0, 0, st});
	while(pq.size()) {
		node n = pq.top(); pq.pop();
		if((n.id == st && n.c == 1) || n.v > ans) break;
		// printf("now: (%f, %d, (%d, %d))\n", n.v, n.c, T[n.id].D.X, T[n.id].D.Y);
		if(f(D[n.c][n.id] - n.v) > eps) continue;
		for(auto& it: adj[n.id]) {
			int tc = n.c;
			if(IT[n.id][it.X]) tc = 1 - tc;
			if(D[tc][it.X] > n.v + it.Y) {
				D[tc][it.X] = n.v + it.Y;
				rec.push_back({tc, it.X});
				pq.push({D[tc][it.X], tc, it.X});
			}
		}
	}
	ans = min(ans, D[1][st]);
	for(auto& it: rec) D[it.X][it.Y] = 1e9;
}

void make_edge(int u, int v, double c) {
	adj[u].push_back({v, c});
	adj[v].push_back({u, c});
}

int main() {
	scanf("%d%d",&N,&S);
	// N = 100; S = 100;
	ans = 8.0*S;
	for(int i=1; i<=N; i++) {
		scanf("%lf%lf%lf%lf", &A[i].S.X, &A[i].S.Y, &A[i].E.X, &A[i].E.Y);
		// A[i].S = {i, 100}; A[i].E = {i+1, 100};
		T.push_back({A[i].S, i, 0});
		T.push_back({A[i].E, i, 0});
	}
	T.push_back({{S, S}, N+1, 0});
	T.push_back({{S, -S}, N+2, 0});
	T.push_back({{-S, -S}, N+3, 0});
	T.push_back({{-S, S}, N+4, 0});

	int L = T.size();

	for(int i=1; i<=N; i++) {
		make_edge(2*i-2, 2*i-1, 0);
		for(int j=0; j<T.size(); j++) {
			if(i == T[j].id) continue;
			pdd pu = push(A[i], T[j].D);
			double dp = dst(pu, T[j].D), ds = dst(T[j].D, A[i].S), de = dst(T[j].D, A[i].E);
			if(!ok({T[j].D, pu}) || !on(A[i], pu)) dp = 1e9;
			if(!ok({T[j].D, A[i].S})) ds = 1e9;
			if(!ok({T[j].D, A[i].E})) de = 1e9;
			if(min({ds, de, dp}) == 1e9) continue;
			if(dp <= ds && dp <= de) {
				int u = T.size();
				T.push_back({pu, i, 1});
				make_edge(u, j, dp);
				make_edge(u, 2*i-2, 0);
				continue;
			}
			if(ds <= de) make_edge(j, 2*i-2, ds);
			else make_edge(j, 2*i-1, de);
		}
	}

	for(int i=2*N; i<2*N+4; i++) {
		for(int j=i+1; j<2*N+4; j++) {
			if(!ok({T[i].D, T[j].D})) continue;
			make_edge(i, j, dst(T[i].D, T[j].D));
		}
	}

	K = T.size();

	for(int i=0; i<K; i++) {
		for(int j=i+1; j<K; j++) {
			if(its({T[i].D, T[j].D}, I)) IT[i][j] = IT[j][i] = 1;
		}
	}

	// printf("K: %d\n", K);
	// for(auto& it: T) {
	// 	printf("position(%f, %f), id: %d, pushed?: %d\n", it.D.X, it.D.Y, it.id, it.ps);
	// }

	srand(14341);
	for(int i=0; i<K; i++) D[0][i] = D[1][i] = 1e9;
	for(int i=0; i<2*N; i+=2) if(N <= 50 || rand()%2 == 1) dijk(i);
	for(int i=2*N; i<2*N+4; i++) dijk(i);
	printf("%.10f", ans);
	return 0;
}

Compilation message

fences.cpp: In function 'int main()':
fences.cpp:108:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0; j<T.size(); j++) {
                ~^~~~~~~~~
fences.cpp:104:6: warning: unused variable 'L' [-Wunused-variable]
  int L = T.size();
      ^
fences.cpp:90:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&N,&S);
  ~~~~~^~~~~~~~~~~~~~
fences.cpp:94:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lf%lf%lf%lf", &A[i].S.X, &A[i].S.Y, &A[i].E.X, &A[i].E.Y);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fences.cpp: In function 'int CCWs(pdd, pdd, pdd)':
fences.cpp:26:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23928 KB Output is correct
2 Correct 23 ms 23800 KB Output is correct
3 Correct 23 ms 23800 KB Output is correct
4 Correct 23 ms 23800 KB Output is correct
5 Correct 23 ms 23800 KB Output is correct
6 Correct 23 ms 23928 KB Output is correct
7 Correct 23 ms 23928 KB Output is correct
8 Correct 22 ms 23800 KB Output is correct
9 Correct 22 ms 23800 KB Output is correct
10 Correct 23 ms 23800 KB Output is correct
11 Correct 24 ms 23800 KB Output is correct
12 Correct 24 ms 23928 KB Output is correct
13 Correct 23 ms 23928 KB Output is correct
14 Correct 24 ms 23928 KB Output is correct
15 Correct 24 ms 23800 KB Output is correct
16 Correct 23 ms 23928 KB Output is correct
17 Correct 23 ms 23800 KB Output is correct
18 Correct 23 ms 23800 KB Output is correct
19 Correct 23 ms 23928 KB Output is correct
20 Correct 23 ms 23928 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23928 KB Output is correct
2 Correct 23 ms 23800 KB Output is correct
3 Correct 23 ms 23800 KB Output is correct
4 Correct 23 ms 23800 KB Output is correct
5 Correct 23 ms 23800 KB Output is correct
6 Correct 23 ms 23928 KB Output is correct
7 Correct 23 ms 23928 KB Output is correct
8 Correct 22 ms 23800 KB Output is correct
9 Correct 22 ms 23800 KB Output is correct
10 Correct 23 ms 23800 KB Output is correct
11 Correct 24 ms 23800 KB Output is correct
12 Correct 24 ms 23928 KB Output is correct
13 Correct 23 ms 23928 KB Output is correct
14 Correct 24 ms 23928 KB Output is correct
15 Correct 24 ms 23800 KB Output is correct
16 Correct 23 ms 23928 KB Output is correct
17 Correct 23 ms 23800 KB Output is correct
18 Correct 23 ms 23800 KB Output is correct
19 Correct 23 ms 23928 KB Output is correct
20 Correct 23 ms 23928 KB Output is correct
21 Correct 22 ms 23800 KB Output is correct
22 Correct 23 ms 24056 KB Output is correct
23 Correct 23 ms 24056 KB Output is correct
24 Correct 23 ms 23928 KB Output is correct
25 Correct 23 ms 23928 KB Output is correct
26 Correct 23 ms 23920 KB Output is correct
27 Correct 23 ms 23868 KB Output is correct
28 Correct 23 ms 23900 KB Output is correct
29 Correct 23 ms 23928 KB Output is correct
30 Correct 23 ms 23956 KB Output is correct
31 Correct 23 ms 23928 KB Output is correct
32 Correct 23 ms 23928 KB Output is correct
33 Correct 24 ms 24056 KB Output is correct
34 Correct 24 ms 23928 KB Output is correct
35 Correct 24 ms 24312 KB Output is correct
36 Correct 24 ms 24316 KB Output is correct
37 Correct 23 ms 23928 KB Output is correct
38 Correct 23 ms 23848 KB Output is correct
39 Correct 23 ms 24056 KB Output is correct
40 Correct 23 ms 23928 KB Output is correct
41 Correct 24 ms 23924 KB Output is correct
42 Correct 24 ms 24056 KB Output is correct
43 Correct 24 ms 24568 KB Output is correct

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23928 KB Output is correct
2 Correct 23 ms 23800 KB Output is correct
3 Correct 23 ms 23800 KB Output is correct
4 Correct 23 ms 23800 KB Output is correct
5 Correct 23 ms 23800 KB Output is correct
6 Correct 23 ms 23928 KB Output is correct
7 Correct 23 ms 23928 KB Output is correct
8 Correct 22 ms 23800 KB Output is correct
9 Correct 22 ms 23800 KB Output is correct
10 Correct 23 ms 23800 KB Output is correct
11 Correct 24 ms 23800 KB Output is correct
12 Correct 24 ms 23928 KB Output is correct
13 Correct 23 ms 23928 KB Output is correct
14 Correct 24 ms 23928 KB Output is correct
15 Correct 24 ms 23800 KB Output is correct
16 Correct 23 ms 23928 KB Output is correct
17 Correct 23 ms 23800 KB Output is correct
18 Correct 23 ms 23800 KB Output is correct
19 Correct 23 ms 23928 KB Output is correct
20 Correct 23 ms 23928 KB Output is correct
21 Correct 22 ms 23800 KB Output is correct
22 Correct 23 ms 24056 KB Output is correct
23 Correct 23 ms 24056 KB Output is correct
24 Correct 23 ms 23928 KB Output is correct
25 Correct 23 ms 23928 KB Output is correct
26 Correct 23 ms 23920 KB Output is correct
27 Correct 23 ms 23868 KB Output is correct
28 Correct 23 ms 23900 KB Output is correct
29 Correct 23 ms 23928 KB Output is correct
30 Correct 23 ms 23956 KB Output is correct
31 Correct 23 ms 23928 KB Output is correct
32 Correct 23 ms 23928 KB Output is correct
33 Correct 24 ms 24056 KB Output is correct
34 Correct 24 ms 23928 KB Output is correct
35 Correct 24 ms 24312 KB Output is correct
36 Correct 24 ms 24316 KB Output is correct
37 Correct 23 ms 23928 KB Output is correct
38 Correct 23 ms 23848 KB Output is correct
39 Correct 23 ms 24056 KB Output is correct
40 Correct 23 ms 23928 KB Output is correct
41 Correct 24 ms 23924 KB Output is correct
42 Correct 24 ms 24056 KB Output is correct
43 Correct 24 ms 24568 KB Output is correct
44 Execution timed out 1097 ms 241920 KB Time limit exceeded
45 Halted 0 ms 0 KB -