oj.uz

답안 #367292

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
367292 2021-02-16T19:17:03 Z MrRobot_28 Planine (COCI21_planine) C++17
110 / 110
 682 ms 88388 KB 
#include<bits/stdc++.h>
using namespace std;
#define X first
#define Y second
#define int long long
int crossproduct(pair <int, int> a, pair <int, int> b, pair <int, int> c)
{
    return (b.X- a.X) * (c.Y - a.Y) - (b.Y - a.Y) * (c.X - a.X);
}
int n, h;
vector <pair <int, int> > funct(vector <pair <int, int> > x)
{
    vector <pair <int, int> > res(n / 2 - 1);
    vector <pair <int, int> > st;
    for(int i = 1; i < n - 1; i++)
    {
        while(st.size() > 1 && crossproduct(st[st.size() - 2], st.back(), x[i]) >= 0)
        {
            st.pop_back();
        }
        st.push_back(x[i]);
        if(!(i & 1))
        {
            auto [x1, y1] = st.rbegin()[0];
            auto [x2, y2] = st.rbegin()[1];
            /*int x1 = st[st.size() - 2].X;
            int y1 = st[st.size() - 2].Y;
            int x2 = x[i].X;
            int y2 = x[i].Y;*/
            int x0 = (x1 - x2) * (h - y2) + x2 * (y1 - y2);
            int y0 = y1 - y2;
          //  cout << st.size() << "\n";
            res[i / 2 - 1] = {x0, y1 - y2};
        }
    }
    return res;
}
bool cmp(pair <pair <int, int>, pair <int, int> > a, pair <pair <int, int>, pair <int, int> > b)
{
    if(a.X.X * b.X.Y == a.X.Y * b.X.X)
    {
        return a.Y.X < b.Y.X;
    }
    return a.X.X * b.X.Y < a.X.Y * b.X.X;
}
signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> h;
    vector <pair <int, int> > x(n);
    for(int i = 0; i < n; i++)
    {
        cin >> x[i].X >> x[i].Y;
    }
    vector <pair <int, int> > a = funct(x);
    reverse(x.begin(), x.end());
    for(int i = 0; i < n; i++)
    {
        x[i].X *= -1;
    }
    vector <pair <int, int> > b = funct(x);
    reverse(b.begin(), b.end());
    for(int i = 0; i < b.size(); i++)
    {
        b[i].X *= -1;
    }
    int ans = 0;
    vector <pair <pair <int, int>, pair <int, int> > > scan;
    for(int i = 0; i < n / 2 - 1; i++)
    {
        scan.push_back({a[i], {-1, i}});
        scan.push_back({b[i], {1, i}});
    }
    sort(scan.begin(), scan.end(), cmp);
    set <int> s;
    for(int i = 0; i < scan.size(); i++)
    {
        int t = scan[i].Y.X;
        if(t == -1)
        {
            s.insert(scan[i].Y.Y);
        }
        else if(s.find(scan[i].Y.Y) != s.end())
        {
            ans++;
            s.clear();
        }
    }
    cout << ans;
    return 0;
}

Compilation message

Main.cpp: In function 'std::vector<std::pair<long long int, long long int> > funct(std::vector<std::pair<long long int, long long int> >)':
Main.cpp:31:17: warning: unused variable 'y0' [-Wunused-variable]
   31 |             int y0 = y1 - y2;
      |                 ^~
Main.cpp: In function 'int main()':
Main.cpp:65:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   65 |     for(int i = 0; i < b.size(); i++)
      |                    ~~^~~~~~~~~~
Main.cpp:78:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<std::pair<long long int, long long int>, std::pair<long long int, long long int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |     for(int i = 0; i < scan.size(); i++)
      |                    ~~^~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 1484 KB Output is correct
2 Correct 5 ms 1484 KB Output is correct
3 Correct 5 ms 1484 KB Output is correct
4 Correct 44 ms 10192 KB Output is correct
5 Correct 43 ms 10192 KB Output is correct
6 Correct 47 ms 10192 KB Output is correct
7 Correct 493 ms 88388 KB Output is correct
8 Correct 479 ms 88388 KB Output is correct
9 Correct 495 ms 88328 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 492 KB Output is correct
2 Correct 1 ms 492 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 2 ms 492 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 492 KB Output is correct
7 Correct 1 ms 364 KB Output is correct

Subtask #3
60.0 / 60.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 1484 KB Output is correct
2 Correct 5 ms 1484 KB Output is correct
3 Correct 5 ms 1484 KB Output is correct
4 Correct 44 ms 10192 KB Output is correct
5 Correct 43 ms 10192 KB Output is correct
6 Correct 47 ms 10192 KB Output is correct
7 Correct 493 ms 88388 KB Output is correct
8 Correct 479 ms 88388 KB Output is correct
9 Correct 495 ms 88328 KB Output is correct
10 Correct 2 ms 492 KB Output is correct
11 Correct 1 ms 492 KB Output is correct
12 Correct 1 ms 364 KB Output is correct
13 Correct 2 ms 492 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 492 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 463 ms 88388 KB Output is correct
18 Correct 474 ms 88360 KB Output is correct
19 Correct 44 ms 10192 KB Output is correct
20 Correct 474 ms 88388 KB Output is correct
21 Correct 48 ms 10192 KB Output is correct
22 Correct 468 ms 88388 KB Output is correct
23 Correct 1 ms 364 KB Output is correct
24 Correct 493 ms 88388 KB Output is correct
25 Correct 44 ms 10192 KB Output is correct
26 Correct 682 ms 88388 KB Output is correct
27 Correct 23 ms 5212 KB Output is correct