oj.uz

답안 #132033

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
132033 2019-07-18T08:27:12 Z 이온조(#3189) Fences (JOI18_fences) C++14
18 / 100
 28 ms 24060 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(12341);
	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()%3 == 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

# 결과 실행 시간 메모리 Grader output
1 Correct 23 ms 23800 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 24036 KB Output is correct
5 Correct 22 ms 23800 KB Output is correct
6 Correct 23 ms 23800 KB Output is correct
7 Correct 23 ms 23800 KB Output is correct
8 Correct 23 ms 23800 KB Output is correct
9 Correct 23 ms 23804 KB Output is correct
10 Correct 23 ms 23800 KB Output is correct
11 Correct 23 ms 23928 KB Output is correct
12 Correct 23 ms 23928 KB Output is correct
13 Correct 24 ms 23928 KB Output is correct
14 Correct 28 ms 23928 KB Output is correct
15 Correct 23 ms 23800 KB Output is correct
16 Correct 27 ms 24060 KB Output is correct
17 Correct 23 ms 23800 KB Output is correct
18 Correct 28 ms 23928 KB Output is correct
19 Correct 27 ms 23808 KB Output is correct
20 Correct 24 ms 23900 KB Output is correct

Subtask #2
0 / 33.0

# 결과 실행 시간 메모리 Grader output
1 Correct 23 ms 23800 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 24036 KB Output is correct
5 Correct 22 ms 23800 KB Output is correct
6 Correct 23 ms 23800 KB Output is correct
7 Correct 23 ms 23800 KB Output is correct
8 Correct 23 ms 23800 KB Output is correct
9 Correct 23 ms 23804 KB Output is correct
10 Correct 23 ms 23800 KB Output is correct
11 Correct 23 ms 23928 KB Output is correct
12 Correct 23 ms 23928 KB Output is correct
13 Correct 24 ms 23928 KB Output is correct
14 Correct 28 ms 23928 KB Output is correct
15 Correct 23 ms 23800 KB Output is correct
16 Correct 27 ms 24060 KB Output is correct
17 Correct 23 ms 23800 KB Output is correct
18 Correct 28 ms 23928 KB Output is correct
19 Correct 27 ms 23808 KB Output is correct
20 Correct 24 ms 23900 KB Output is correct
21 Correct 22 ms 23804 KB Output is correct
22 Correct 23 ms 24052 KB Output is correct
23 Correct 23 ms 24056 KB Output is correct
24 Incorrect 23 ms 23928 KB Output isn't correct
25 Halted 0 ms 0 KB -

Subtask #3
0 / 49.0

# 결과 실행 시간 메모리 Grader output
1 Correct 23 ms 23800 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 24036 KB Output is correct
5 Correct 22 ms 23800 KB Output is correct
6 Correct 23 ms 23800 KB Output is correct
7 Correct 23 ms 23800 KB Output is correct
8 Correct 23 ms 23800 KB Output is correct
9 Correct 23 ms 23804 KB Output is correct
10 Correct 23 ms 23800 KB Output is correct
11 Correct 23 ms 23928 KB Output is correct
12 Correct 23 ms 23928 KB Output is correct
13 Correct 24 ms 23928 KB Output is correct
14 Correct 28 ms 23928 KB Output is correct
15 Correct 23 ms 23800 KB Output is correct
16 Correct 27 ms 24060 KB Output is correct
17 Correct 23 ms 23800 KB Output is correct
18 Correct 28 ms 23928 KB Output is correct
19 Correct 27 ms 23808 KB Output is correct
20 Correct 24 ms 23900 KB Output is correct
21 Correct 22 ms 23804 KB Output is correct
22 Correct 23 ms 24052 KB Output is correct
23 Correct 23 ms 24056 KB Output is correct
24 Incorrect 23 ms 23928 KB Output isn't correct
25 Halted 0 ms 0 KB -