Cod sursa(job #324056)
Utilizator | Data | 14 iunie 2009 15:24:40 | |
---|---|---|---|
Problema | Robot | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 18.77 kb |
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <math.h>
#include <vector>
#include <algorithm>
using namespace std;
#define sz(a) int((a).size())
#define pb push_back
#define mp make_pair
#define x first
#define y second
#define punct pair<int, int>
#define punct2 pair<double, double>
#define tr(c, it) for (typeof((c).begin()) it = (c).begin(); it != (c).end(); ++it)
#define all(c) (c).begin(), (c).end()
#define inf 1e9
#define Pmax 2600
punct finish;
vector< punct > robot;
vector< vector< punct> > obstacol;
char viz[Pmax];
int st[Pmax];
vector< punct > v;
punct2 inter;
void readdata() {
freopen("robot.in", "r", stdin);
freopen("robot.out", "w", stdout);
int i, j, a, b, n, m;
vector<punct> aux;
scanf("%d", &n);
for (i = 0; i < n; ++i) {
scanf("%d %d", &a, &b);
robot.pb( mp(a, b) );
}
scanf("%d", &m);
for (i = 1; i <= m; ++i) {
scanf("%d", &n);
for (aux.clear(), j = 0; j < n; ++j) {
scanf("%d %d", &a, &b);
aux.pb( mp(a, b) );
}
obstacol.pb(aux);
}
scanf("%d %d", &finish.x, &finish.y);
}
int sign(punct a, punct b, punct c) {
int prod = (a.x-c.x)*(b.y-c.y) - (b.x-c.x)*(a.y-c.y);
return (prod == 0 ? 0 : prod < 0 ? -1 : 1);
}
void convex_hull(vector< punct > &v) {
int i, p = 1, n;
vector< punct> aux;
sort( all(v) );
v.resize( unique(all(v)) - v.begin() );
n = sz(v);
memset(viz, 0, sizeof(viz));
st[ st[0] = 1 ] = 0;
for (i = 1; i >= 0; i += (p = (i == n-1) ? -p : p))
if (!viz[i]) {
while (st[0] >= 2 && sign(v[i], v[st[ st[0] ]], v[st[ st[0]-1 ]]) <= 0)
viz[ st[ st[0]-- ] ] = 0;
viz[ st[++st[0]] = i ] = 1;
}
for (i = 1; i < st[0]; ++i)
aux.pb(v[st[i]]);
v = aux;
}
void refa_obstacol(vector< punct > &v) {
int i, j, lim = sz(v);
for (i = 0; i < lim; ++i)
for (j = 0; j < sz(robot); ++j)
v.pb( mp(v[i].x + robot[0].x - robot[j].x, v[i].y + robot[0].y - robot[j].y) );
convex_hull(v);
}
void refa_finish() {
int best = robot[0].y;
tr(robot, it) best = min(best, it->y);
finish.y += robot[0].y-best;
}
inline double sqr(int a) {
return double(a*a);
}
int apartine(punct a, punct b, punct c) {
punct p1 = min(b, c), p2 = max(b, c);
return ((a.y-p1.y)*(p2.x-p1.x) == (a.x-p1.x)*(p2.y-p1.y) && a >= p1 && a <= p2);
}
int coliniar(punct a, punct b, punct c) {
return (a.y-b.y)*(c.x-b.x) == (a.x-b.x)*(c.y-b.y);
}
int contur(punct a, vector< punct > &v) {
for (int i = 0; i < sz(v)-1; ++i)
if (apartine(a, v[i], v[i+1]))
return 1;
return 0;
}
int arie_poligon(vector< punct > &v) {
int ret = 0, i;
for (i = 0; i < sz(v)-1; ++i)
ret += v[i].x*v[i+1].y - v[i+1].x*v[i].y;
return abs(ret);
}
int arie_punct(punct a, vector< punct > &v) {
vector< punct > aux;
int ret = 0, i;
for (i = 0; i < sz(v)-1; ++i) {
aux.clear();
aux.pb(v[i]), aux.pb(v[i+1]), aux.pb(a);
aux.pb(v[i]);
ret += arie_poligon(aux);
}
return ret;
}
int intersection(punct a, punct b, punct c, punct d) {
double A, B, C, A2, B2, C2, det;
A = b.y-a.y;
B = a.x-b.x;
C = -a.y*(b.x-a.x) + a.x*(b.y-a.y);
A2 = d.y-c.y;
B2 = c.x-d.x;
C2 = -c.y*(d.x-c.x) + c.x*(d.y-c.y);
det = A*B2 - B*A2;
if (det == 0) return 0;
inter = mp( (B2*C - B*C2)/det, (A*C2 - A2*C)/det );
return (sign(c, b, a) * sign(d, b, a) <= 0 && sign(a, c, d) * sign(b, c, d) <= 0);
}
int intersecteaza(punct a, punct b, vector< punct > &v) {
int i;
//cazul in care a si b apartin dreptei suport a unei laturi
for (i = 0; i < sz(v)-1; ++i)
if (coliniar(a, v[i], v[i+1]) && coliniar(b, v[i], v[i+1]))
return 0;
//afla care din puncte se afla pe conturul poligonului
char v1 = contur(a, v), v2 = contur(b, v);
if (v1 && v2) return 1;
//cazul in care un punct apartine interiorului poligonului
int ap = arie_poligon(v), a1 = arie_punct(a, v), a2 = arie_punct(b, v);
if (a1 == ap && !v1) return 1;
if (a2 == ap && !v2) return 1;
vector< punct2 > aux;
for (i = 0; i < sz(v)-1; ++i)
if (intersection(a, b, v[i], v[i+1]))
aux.pb(inter);
sort(all(aux));
aux.resize( unique(all(aux)) - aux.begin() );
return sz(aux) > 1;
}
double afla_distanta(punct a, punct b) {
double ret = sqrt(sqr(a.x-b.x) + sqr(a.y-b.y));
int i;
if (a == b) return ret;
for (i = 0; i < sz(obstacol); ++i)
if (intersecteaza(a, b, obstacol[i]))
return inf;
return ret;
}
void solve() {
int i, j;
//redu robotul la un singur punct;
sort(all(robot));
for (i = 0; i < sz(obstacol); ++i)
refa_obstacol(obstacol[i]);
refa_finish();
//afla punctele ce pot fi vizitate si matricea de adiacenta
v.pb(robot[0]);
for (i = 0; i < sz(obstacol); ++i)
for (j = 0; j < sz(obstacol[i]); ++j)
v.pb(obstacol[i][j]);
v.pb(finish);
vector< vector< double > > c( sz(v), sz(v) );
for (i = 0; i < sz(obstacol); ++i)
obstacol[i].pb( obstacol[i][0] );
for (i = 0; i < sz(v); ++i)
for (j = 0; j < sz(v); ++j)
c[i][j] = afla_distanta(v[i], v[j]);
//afla drumul cel mai scurt si afiseaza
int n = sz(v)-1;
vector< double > d(n+1, inf);
vector< char > viz(n+1, 0);
double best;
int poz;
d[0] = 0;
while (!viz[n]) {
best = inf;
for (i = 0; i <= n; ++i)
if (!viz[i] && d[i] < best) {
best = d[i];
poz = i;
}
viz[poz] = 1;
for (i = 0; i <= n; ++i)
d[i] = min(d[i], best + c[poz][i]);
}
printf("%lf\n", d[n]);
}
int main() {
readdata();
solve();
return 0;
}