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Submission #538172

# Submission time Handle Problem Language Result Execution time Memory
538172 2022-03-16T07:24:47 Z siewjh Planine (COCI21_planine) C++17
50 / 110
 522 ms 23888 KB 
#include <bits/stdc++.h>
typedef double ld;
using namespace std;
int nums; ld h;
const ld error = 1e-9;
struct pt{
    ld x, y;
};
struct hull{
    vector<pt> v;
    ld intersect(pt a, pt b){
        return (h - b.y) / (a.y - b.y) * (a.x - b.x) + b.x;
    }
    void insert(pt p){
        while (!v.empty() && v.back().y <= p.y) v.pop_back();
        v.push_back(p);
    }
    ld query(pt p){
        while (v.size() >= 2 && abs(intersect(p, v.back()) - p.x) >= abs(intersect(p, v[v.size() - 2]) - p.x)) v.pop_back();
        return intersect(p, v.back());
    }
};
bool cmp(pair<ld, ld> a, pair<ld, ld> b){
    return 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<ld, ld> range[valley];
    hull left;
    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;
    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; ld last_pos = -1e18;
    for (int i = 0; i < valley; i++)
        if (range[i].first > last_pos + error){
            ans++;
            last_pos = range[i].second;
        }
    cout << ans;
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 468 KB Output is correct
2 Correct 5 ms 468 KB Output is correct
3 Correct 6 ms 468 KB Output is correct
4 Correct 44 ms 2644 KB Output is correct
5 Correct 49 ms 2636 KB Output is correct
6 Correct 50 ms 2628 KB Output is correct
7 Correct 491 ms 23764 KB Output is correct
8 Correct 502 ms 23888 KB Output is correct
9 Correct 522 ms 23776 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory 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 1 ms 212 KB Output is correct

Subtask #3
0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 468 KB Output is correct
2 Correct 5 ms 468 KB Output is correct
3 Correct 6 ms 468 KB Output is correct
4 Correct 44 ms 2644 KB Output is correct
5 Correct 49 ms 2636 KB Output is correct
6 Correct 50 ms 2628 KB Output is correct
7 Correct 491 ms 23764 KB Output is correct
8 Correct 502 ms 23888 KB Output is correct
9 Correct 522 ms 23776 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 1 ms 212 KB Output is correct
17 Correct 477 ms 23764 KB Output is correct
18 Incorrect 499 ms 23792 KB Output isn't correct
19 Halted 0 ms 0 KB -