Cod sursa(job #594865)

Utilizator rudarelLup Ionut rudarel Data 10 iunie 2011 08:09:01
Problema Robot Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 6.13 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 30000
 
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;
}