oj.uz

Submission #132132

# Submission time Handle Problem Language Result Execution time Memory
132132 2019-07-18T10:40:22 Z onjo0127 Fences (JOI18_fences) C++11
0 / 100
 30 ms 23972 KB 
#pragma GCC optimize ("Ofast")
#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) {
				make_edge(j, 2*i-2, dp);
				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);
	// }
 
	for(int i=0; i<K; i++) D[0][i] = D[1][i] = 1e9;
	for(int i=0; i<2*N; i+=2) 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:109:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0; j<T.size(); j++) {
                ~^~~~~~~~~
fences.cpp:105:6: warning: unused variable 'L' [-Wunused-variable]
  int L = T.size();
      ^
fences.cpp:91:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&N,&S);
  ~~~~~^~~~~~~~~~~~~~
fences.cpp:95:8: 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:27:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

Subtask #1
0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 23928 KB Output is correct
2 Correct 25 ms 23800 KB Output is correct
3 Correct 30 ms 23800 KB Output is correct
4 Correct 24 ms 23928 KB Output is correct
5 Correct 26 ms 23800 KB Output is correct
6 Correct 24 ms 23800 KB Output is correct
7 Correct 28 ms 23800 KB Output is correct
8 Correct 24 ms 23800 KB Output is correct
9 Correct 24 ms 23800 KB Output is correct
10 Correct 24 ms 23800 KB Output is correct
11 Correct 27 ms 23972 KB Output is correct
12 Correct 25 ms 23928 KB Output is correct
13 Correct 24 ms 23800 KB Output is correct
14 Correct 24 ms 23928 KB Output is correct
15 Correct 25 ms 23800 KB Output is correct
16 Correct 24 ms 23928 KB Output is correct
17 Incorrect 24 ms 23800 KB Output isn't correct
18 Halted 0 ms 0 KB -

Subtask #2
0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 23928 KB Output is correct
2 Correct 25 ms 23800 KB Output is correct
3 Correct 30 ms 23800 KB Output is correct
4 Correct 24 ms 23928 KB Output is correct
5 Correct 26 ms 23800 KB Output is correct
6 Correct 24 ms 23800 KB Output is correct
7 Correct 28 ms 23800 KB Output is correct
8 Correct 24 ms 23800 KB Output is correct
9 Correct 24 ms 23800 KB Output is correct
10 Correct 24 ms 23800 KB Output is correct
11 Correct 27 ms 23972 KB Output is correct
12 Correct 25 ms 23928 KB Output is correct
13 Correct 24 ms 23800 KB Output is correct
14 Correct 24 ms 23928 KB Output is correct
15 Correct 25 ms 23800 KB Output is correct
16 Correct 24 ms 23928 KB Output is correct
17 Incorrect 24 ms 23800 KB Output isn't correct
18 Halted 0 ms 0 KB -

Subtask #3
0 / 49.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 23928 KB Output is correct
2 Correct 25 ms 23800 KB Output is correct
3 Correct 30 ms 23800 KB Output is correct
4 Correct 24 ms 23928 KB Output is correct
5 Correct 26 ms 23800 KB Output is correct
6 Correct 24 ms 23800 KB Output is correct
7 Correct 28 ms 23800 KB Output is correct
8 Correct 24 ms 23800 KB Output is correct
9 Correct 24 ms 23800 KB Output is correct
10 Correct 24 ms 23800 KB Output is correct
11 Correct 27 ms 23972 KB Output is correct
12 Correct 25 ms 23928 KB Output is correct
13 Correct 24 ms 23800 KB Output is correct
14 Correct 24 ms 23928 KB Output is correct
15 Correct 25 ms 23800 KB Output is correct
16 Correct 24 ms 23928 KB Output is correct
17 Incorrect 24 ms 23800 KB Output isn't correct
18 Halted 0 ms 0 KB -