oj.uz

Submission #397644

# Submission time Handle Problem Language Result Execution time Memory
397644 2021-05-02T16:37:52 Z MrRobot_28 Geometrija (COCI21_geometrija) C++17
50 / 110
 1000 ms 8176 KB 
#include<bits/stdc++.h>
using namespace std;
#define X first
#define Y second
#define int long long
#define sz(a) (int)a.size()
const int mod = 1e9 + 7;
const int N = 2e5+ 100;
int crossproduct(pair <int, int> a, pair <int, int> b)
{
    return a.X * b.Y - a.Y * b.X;
}
bool cmp(pair <pair <int, int>, int> a, pair <pair <int, int>, int> b)
{
    if(a.X.X * b.X.X < 0)
    {
        return a.X.X > b.X.X;
    }
    if(a.X.X == 0)
    {
        return b.X.X < 0 || a.X.Y > 0;
    }
    if(b.X.X == 0)
    {
        return a.X.X > 0 && b.X.Y < 0;
    }
    return crossproduct(a.X, b.X) < 0;
}
signed main()
{
  //  ifstream cin("input1.txt.4c");
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n;
    cin >> n;
    vector <pair <int, int> > x(n);
    int cnt[n][n];
    for(int i = 0; i < n; i++)
    {
        for(int j = 0; j < n; j++)
        {
            cnt[i][j] = 0;
        }
    }
    for(int i = 0; i < n; i++)
    {
        cin >> x[i].X >> x[i].Y;
    }
    vector <int> coun(n);
    for(int i = 0; i < n; i++)
    {
        vector <pair <pair <int, int>, int> > t;
        for(int j = 0; j < n; j++)
        {
            if(i != j)
            {
                t.push_back({{x[j].X - x[i].X, x[j].Y - x[i].Y}, j});
            }
        }
        sort(t.begin(), t.end(), cmp);
        int it = 0;
        //cout << i << "\n";
        for(int j = 0; j < n - 1; j++)
        {
        //    cout << t[j].X.X << " " << t[j].X.Y << " " << t[j].Y << "\n";
            while(it != n - 1 + j && (j == it  || crossproduct(t[j].X, t[it % (n - 1)].X) < 0))
            {
                it++;
            }
          //  cout << "A " << it << " ";
            coun[j] = (n - 1 + j) - it;
            //cout << coun[j] << "\n";
        }
        int sum = 0;
        it = 1;
        for(int j = 1; j < n - 1; j++)
        {
            sum += coun[j];
        }
        for(int j = 0; j < n - 1; j++)
        {
            while(it != n - 1 + j && (it <= j || crossproduct(t[j].X, t[it % (n - 1)].X) < 0))
            {
                sum -= coun[it % (n - 1)];
                it++;
            }
            int k = it - j - 1;
         //   cout << i << " " << t[j].Y << " " << sum + k * (k - 1) / 2 << "\n";
            cnt[i][t[j].Y] += sum + k * (k - 1) / 2;
            sum += coun[j];
        }
    }
    int ans = 0;
    for(int i = 0; i < n; i++)
    {
        for(int j = i + 1; j < n; j++)
        {
            int d = cnt[i][j] + cnt[j][i];
            int k1 = 0, k2 = 0;
            int A = x[j].Y - x[i].Y;
            int B = x[i].X - x[j].X;
            int C = -x[i].X * A - x[i].Y * B;
            for(int t = 0; t < n; t++)
            {
                if(A * x[t].X + B * x[t].Y + C < 0)
                {
                    k1++;
                }
                else if(A * x[t].X + B * x[t].Y + C > 0)
                {
                    k2++;
                }
            }
            d -= k1 * (k1 - 1) / 2;
            d -= k2 * (k2 - 1) / 2;
      //      cout << d << " ";
            if(d == (n - 2) * (n - 3) / 2)
            {
                ans++;
            }
        }
        //cout << "\n";
    }
    cout << ans;
    return 0;
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 316 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Correct 1 ms 332 KB Output is correct
8 Correct 1 ms 332 KB Output is correct
9 Correct 1 ms 204 KB Output is correct
10 Correct 1 ms 204 KB Output is correct
11 Correct 1 ms 204 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 316 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Correct 1 ms 332 KB Output is correct
8 Correct 1 ms 332 KB Output is correct
9 Correct 1 ms 204 KB Output is correct
10 Correct 1 ms 204 KB Output is correct
11 Correct 1 ms 204 KB Output is correct
12 Correct 22 ms 588 KB Output is correct
13 Correct 22 ms 592 KB Output is correct
14 Correct 17 ms 576 KB Output is correct
15 Correct 15 ms 564 KB Output is correct
16 Correct 20 ms 656 KB Output is correct
17 Correct 21 ms 588 KB Output is correct
18 Correct 21 ms 648 KB Output is correct
19 Correct 22 ms 644 KB Output is correct
20 Correct 20 ms 636 KB Output is correct
21 Correct 20 ms 640 KB Output is correct
22 Correct 22 ms 588 KB Output is correct
23 Correct 21 ms 648 KB Output is correct

Subtask #3
0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 332 KB Output is correct
4 Correct 1 ms 316 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Correct 1 ms 332 KB Output is correct
8 Correct 1 ms 332 KB Output is correct
9 Correct 1 ms 204 KB Output is correct
10 Correct 1 ms 204 KB Output is correct
11 Correct 1 ms 204 KB Output is correct
12 Correct 22 ms 588 KB Output is correct
13 Correct 22 ms 592 KB Output is correct
14 Correct 17 ms 576 KB Output is correct
15 Correct 15 ms 564 KB Output is correct
16 Correct 20 ms 656 KB Output is correct
17 Correct 21 ms 588 KB Output is correct
18 Correct 21 ms 648 KB Output is correct
19 Correct 22 ms 644 KB Output is correct
20 Correct 20 ms 636 KB Output is correct
21 Correct 20 ms 640 KB Output is correct
22 Correct 22 ms 588 KB Output is correct
23 Correct 21 ms 648 KB Output is correct
24 Execution timed out 1083 ms 8176 KB Time limit exceeded
25 Halted 0 ms 0 KB -