oj.uz

답안 #538367

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
538367 2022-03-16T16:40:39 Z siewjh Planine (COCI21_planine) C++17
110 / 110
 302 ms 51912 KB 
#include <bits/stdc++.h>
typedef long double ld;
typedef long long ll;
using namespace std;
int nums; ll h;
bool asc;
struct pt{
    ll x, y;
};
struct hull{
    vector<pt> v;
    bool ccw(pt a, pt b, pt c){
        return a.x * (b.y - c.y) + b.x * (c.y - a.y) + c.x * (a.y - b.y) > 0;
    }
    bool cw(pt a, pt b, pt c){
        return a.x * (b.y - c.y) + b.x * (c.y - a.y) + c.x * (a.y - b.y) < 0;
    }
    void insert(pt p){
        if (asc) while (v.size() >= 2 && ccw(v[v.size() - 2], v.back(), p)) v.pop_back();
        else while (v.size() >= 2 && cw(v[v.size() - 2], v.back(), p)) v.pop_back();
        v.push_back(p);
    }
    pair<ll, ll> query(pt p){
        insert(p);
        auto a = v[v.size() - 2];
        return {(p.x - a.x) * (h - a.y) + a.x * (p.y - a.y), p.y - a.y};
    }
};
bool cmpfrac(pair<ll, ll> a, pair<ll, ll> b){
    return a.first * b.second < b.first * a.second;
}
bool cmp(pair<pair<ll ,ll>, pair<ll, ll>> a, pair<pair<ll ,ll>, pair<ll, ll>> b){
    return cmpfrac(a.second, b.second);
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    cin >> nums >> h;
    pt vec[nums];
    for (int i = 0; i < nums; i++) cin >> vec[i].x >> vec[i].y;
    int valley = (nums - 3) / 2;
    pair<pair<ll, ll>, pair<ll, ll>> range[valley];
    hull left; asc = 1;
    for (int i = 1, j = 0; i < nums - 1; i++){
        if (i % 2) left.insert(vec[i]);
        else {
            range[j].first = left.query(vec[i]);
            j++;
        }
    }
    hull right; asc = 0;
    for (int i = nums - 2, j = valley - 1; i >= 1; i--){
        if (i % 2) right.insert(vec[i]);
        else {
            range[j].second = right.query(vec[i]);
            j--;
        }
    }
    sort(range, range + valley, cmp);
    int ans = 0; pair<ll, ll> last_pos;
    for (int i = 0; i < valley; i++)
        if (i == 0 || cmpfrac(last_pos, range[i].first)){
            ans++;
            last_pos = range[i].second;
        }
    cout << ans;
}

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 852 KB Output is correct
2 Correct 3 ms 852 KB Output is correct
3 Correct 4 ms 852 KB Output is correct
4 Correct 23 ms 5712 KB Output is correct
5 Correct 22 ms 5712 KB Output is correct
6 Correct 25 ms 5720 KB Output is correct
7 Correct 220 ms 51764 KB Output is correct
8 Correct 259 ms 51828 KB Output is correct
9 Correct 278 ms 51844 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 0 ms 212 KB Output is correct

Subtask #3
60.0 / 60.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 852 KB Output is correct
2 Correct 3 ms 852 KB Output is correct
3 Correct 4 ms 852 KB Output is correct
4 Correct 23 ms 5712 KB Output is correct
5 Correct 22 ms 5712 KB Output is correct
6 Correct 25 ms 5720 KB Output is correct
7 Correct 220 ms 51764 KB Output is correct
8 Correct 259 ms 51828 KB Output is correct
9 Correct 278 ms 51844 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 1 ms 212 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 268 ms 51912 KB Output is correct
18 Correct 243 ms 31708 KB Output is correct
19 Correct 24 ms 4544 KB Output is correct
20 Correct 246 ms 41664 KB Output is correct
21 Correct 33 ms 4436 KB Output is correct
22 Correct 252 ms 45376 KB Output is correct
23 Correct 1 ms 212 KB Output is correct
24 Correct 268 ms 44640 KB Output is correct
25 Correct 25 ms 4536 KB Output is correct
26 Correct 302 ms 45516 KB Output is correct
27 Correct 12 ms 2644 KB Output is correct