oj.uz

Submission #532637

# Submission time Handle Problem Language Result Execution time Memory
532637 2022-03-03T12:29:52 Z stefantaga Geometrija (COCI21_geometrija) C++14
110 / 110
 792 ms 7508 KB 
#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
const double PI = acos(-1);
struct Punct
{
    long long x,y;
};
long long determinant (Punct a,Punct b,Punct c)
{
    return a.x*b.y+b.x*c.y+a.y*c.x-a.y*b.x-b.y*c.x-a.x*c.y;
}
bool compare (Punct a, Punct b)
{
    return a.x<b.x||(a.x==b.x&&a.y<b.y);
}
ll n,i,st[4005],q,viz[4005];
Punct v[1005];
struct Triangle
{
    ll a,b,c;
};
ll ok[1005],primul;
vector <Triangle> triunghiuri;
long long ABS(long long x)
{
    if (x>0)
    {
        return x;
    }
    return -x;
}
bool sgn(ll x)
{
    if (x>=0)
    {
        return 1;
    }
    return 0;
}
bool seinter(pair <Punct,Punct> dreapta1,pair <Punct,Punct> dreapta2)
{
    ll det1=determinant(dreapta1.first,dreapta1.second,dreapta2.first);
    ll det2=determinant(dreapta1.first,dreapta1.second,dreapta2.second);
    ll det3=determinant(dreapta2.first,dreapta2.second,dreapta1.first);
    ll det4=determinant(dreapta2.first,dreapta2.second,dreapta1.second);

    if (!det1||!det2||!det3||!det4)
    {
        return 0;
    }
    if (sgn(det1)==sgn(det2))
    {
        return 0;
    }
    if (sgn(det3)==sgn(det4))
    {
        return 0;
    }
    return 1;
}
ll Marc[1005][1005],j;
vector <pair <int,int>> candidati;
Punct P;
bool compare2(int poz1, int poz2)
{
    Punct a,b;
    a=v[poz1];
    b=v[poz2];
    if (a.x - P.x >= 0 && b.x - P.x < 0)
        return true;
    if (a.x - P.x < 0 && b.x - P.x >= 0)
        return false;
    if (a.x - P.x == 0 && b.x - P.x == 0)
    {
        if (a.y - P.y >= 0 || b.y - P.y >= 0)
            return a.y > b.y;
        return b.y > a.y;
    }

    // compute the cross product of vectors (P -> a) x (P -> b)
    int det = (a.x - P.x) * (b.y - P.y) - (b.x - P.x) * (a.y - P.y);
    if (det < 0)
        return true;
    if (det > 0)
        return false;
}
int main()
{
    ios_base :: sync_with_stdio(false);
    cin.tie(0);
#ifdef HOME
    ifstream cin("date.in");
    ofstream cout("date.out");
#endif // HOME
    cin>>n;
    for (i=1; i<=n; i++)
    {
        cin>>v[i].x>>v[i].y;
    }
    sort (v+1,v+n+1,compare);
    st[++q]=1;
    st[++q]=2;
    viz[1]=viz[2]=1;
    for (i=3; i<=n; i++)
    {
        while (q>1&&determinant(v[st[q-1]],v[st[q]],v[i])<0)
        {
            viz[st[q]]=0;
            q--;
        }
        viz[i]=1;
        st[++q]=i;
    }
    for (i=n; i>=1; i--)
    {
        if (viz[i]==0)
        {
            while (q>1&&determinant(v[st[q-1]],v[st[q]],v[i])<0)
            {
                viz[st[q]]=0;
                q--;
            }
            viz[i]=1;
            st[++q]=i;
        }
    }
    while (q>1&&determinant(v[st[q-1]],v[st[q]],v[1])<0)
    {
        q--;
    }
    for (i=1; i<=q; i++)
    {
        ok[st[i]]=1;
    }
    for (i=1; i<=n; i++)
    {
        if (ok[i]==0)
        {
            primul= i ;
            break;
        }
    }
    ok[primul]=1;
    for (i=1; i<q; i++)
    {
        triunghiuri.push_back({st[i],st[i+1],primul});
    }
    triunghiuri.push_back({st[1],st[q],primul});
    for (i=1; i<=n; i++)
    {
        if (ok[i]==0)
        {
            ll loc=0;
            for (ll j=0; j<triunghiuri.size(); j++)
            {
                ll x=triunghiuri[j].a,y=triunghiuri[j].b,z=triunghiuri[j].c;
                ll val1 = ABS(determinant(v[x],v[y],v[i]));
                ll val2 = ABS(determinant(v[y],v[z],v[i]));
                ll val3 = ABS(determinant(v[z],v[x],v[i]));
                ll valfin = ABS(determinant(v[x],v[y],v[z]));
                if (val1+val2+val3==valfin)
                {
                    loc = j;
                    break;
                }
            }
            Triangle triunghi1= {triunghiuri[loc].a,triunghiuri[loc].b,i};
            Triangle triunghi2= {triunghiuri[loc].a,triunghiuri[loc].c,i};
            Triangle triunghi3= {triunghiuri[loc].b,triunghiuri[loc].c,i};
            triunghiuri.erase(triunghiuri.begin()+loc);
            triunghiuri.push_back(triunghi1);
            triunghiuri.push_back(triunghi2);
            triunghiuri.push_back(triunghi3);
        }
    }
    for (ll j=0; j<triunghiuri.size(); j++)
    {
        ll x=triunghiuri[j].a,y=triunghiuri[j].b,z=triunghiuri[j].c;
        Marc[x][y]=Marc[y][x]=Marc[x][z]=Marc[z][x]=Marc[z][y]=Marc[y][z]=1;
    }
    for (i=1; i<=n; i++)
    {
        for (j=i+1; j<=n; j++)
        {
            if (Marc[i][j])
            {
                candidati.push_back({i,j});
            }
        }
    }
    ll sum=0;
    for (i=0; i<candidati.size(); i++)
    {
        vector <int> neg,poz;
        int ok1=1;
        P = v[candidati[i].first];
        Punct Q = v[candidati[i].second];
        if (P.y<Q.y||(P.y==Q.y&&P.x>Q.x))
        {
            swap(P,Q);
        }
        for (j=1; j<=n; j++)
        {
            if (j==candidati[i].first||j==candidati[i].second)
            {
                continue;
            }
            if (determinant(P,Q,v[j])<0)
            {
                neg.push_back(j);
            }
            else
            {
                poz.push_back(j);
            }
        }
        sort (neg.begin(),neg.end(),compare2);
        sort (poz.begin(),poz.end(),compare2);
        int st=-1;
        for (j=0; j<poz.size(); j++)
        {
            for (int k=0; k<neg.size(); k++)
            {
                if (determinant(v[poz[j]],Q,v[neg[k]])<0&&determinant(v[poz[j]],P,v[neg[k]])>0)
                {
                    ok1=0;
                    break;
                }
            }
            /*while (st+1<(int)neg.size()&&determinant(v[poz[j]],P,v[neg[st+1]])>0)
            {
                st++;
            }
            if (st==-1)
            {
                continue;
            }
            if (determinant(v[poz[j]],Q,v[neg[st]])<0)
            {
                ok1=0;
                break;
            }*/
        }
        sum=sum+ok1;
    }
    cout<<sum;
    return 0;
}

Compilation message

geometrija.cpp: In function 'int main()':
geometrija.cpp:156:27: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<Triangle>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  156 |             for (ll j=0; j<triunghiuri.size(); j++)
      |                          ~^~~~~~~~~~~~~~~~~~~
geometrija.cpp:178:19: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<Triangle>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  178 |     for (ll j=0; j<triunghiuri.size(); j++)
      |                  ~^~~~~~~~~~~~~~~~~~~
geometrija.cpp:194:16: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  194 |     for (i=0; i<candidati.size(); i++)
      |               ~^~~~~~~~~~~~~~~~~
geometrija.cpp:222:20: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  222 |         for (j=0; j<poz.size(); j++)
      |                   ~^~~~~~~~~~~
geometrija.cpp:224:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  224 |             for (int k=0; k<neg.size(); k++)
      |                           ~^~~~~~~~~~~
geometrija.cpp:221:13: warning: unused variable 'st' [-Wunused-variable]
  221 |         int st=-1;
      |             ^~
geometrija.cpp: In function 'bool compare2(int, int)':
geometrija.cpp:88:1: warning: control reaches end of non-void function [-Wreturn-type]
   88 | }
      | ^

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 460 KB Output is correct
2 Correct 1 ms 460 KB Output is correct
3 Correct 1 ms 460 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 0 ms 332 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 460 KB Output is correct
2 Correct 1 ms 460 KB Output is correct
3 Correct 1 ms 460 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 0 ms 332 KB Output is correct
12 Correct 12 ms 1324 KB Output is correct
13 Correct 13 ms 1340 KB Output is correct
14 Correct 9 ms 1100 KB Output is correct
15 Correct 9 ms 1164 KB Output is correct
16 Correct 4 ms 1228 KB Output is correct
17 Correct 11 ms 1312 KB Output is correct
18 Correct 13 ms 1336 KB Output is correct
19 Correct 13 ms 1316 KB Output is correct
20 Correct 10 ms 1484 KB Output is correct
21 Correct 13 ms 1340 KB Output is correct
22 Correct 13 ms 1332 KB Output is correct
23 Correct 13 ms 1228 KB Output is correct

Subtask #3
60.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 460 KB Output is correct
2 Correct 1 ms 460 KB Output is correct
3 Correct 1 ms 460 KB Output is correct
4 Correct 1 ms 460 KB Output is correct
5 Correct 1 ms 460 KB Output is correct
6 Correct 1 ms 460 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 0 ms 332 KB Output is correct
12 Correct 12 ms 1324 KB Output is correct
13 Correct 13 ms 1340 KB Output is correct
14 Correct 9 ms 1100 KB Output is correct
15 Correct 9 ms 1164 KB Output is correct
16 Correct 4 ms 1228 KB Output is correct
17 Correct 11 ms 1312 KB Output is correct
18 Correct 13 ms 1336 KB Output is correct
19 Correct 13 ms 1316 KB Output is correct
20 Correct 10 ms 1484 KB Output is correct
21 Correct 13 ms 1340 KB Output is correct
22 Correct 13 ms 1332 KB Output is correct
23 Correct 13 ms 1228 KB Output is correct
24 Correct 548 ms 7420 KB Output is correct
25 Correct 452 ms 7364 KB Output is correct
26 Correct 552 ms 7508 KB Output is correct
27 Correct 461 ms 7264 KB Output is correct
28 Correct 555 ms 7244 KB Output is correct
29 Correct 344 ms 5904 KB Output is correct
30 Correct 359 ms 5904 KB Output is correct
31 Correct 92 ms 6348 KB Output is correct
32 Correct 92 ms 6428 KB Output is correct
33 Correct 368 ms 6468 KB Output is correct
34 Correct 382 ms 6292 KB Output is correct
35 Correct 779 ms 6860 KB Output is correct
36 Correct 730 ms 7080 KB Output is correct
37 Correct 562 ms 6596 KB Output is correct
38 Correct 766 ms 6476 KB Output is correct
39 Correct 792 ms 7136 KB Output is correct
40 Correct 726 ms 7072 KB Output is correct
41 Correct 513 ms 7336 KB Output is correct
42 Correct 449 ms 7336 KB Output is correct