oj.uz

Submission #513832

# Submission time Handle Problem Language Result Execution time Memory
513832 2022-01-17T16:59:03 Z kartel Planine (COCI21_planine) C++14
110 / 110
 294 ms 40616 KB 
#include <bits/stdc++.h>
//#include<ext/rope>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>

//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("-O3")
//#pragma GCC target("avx2")


#define in(x) freopen(x, "r", stdin)
#define out(x) freopen(x, "w", stdout)
#define F first
#define S second
#define pb push_back
#define pri(x) cout << x << endl
#define sz(x) int(x.size())
#define el '\n'
#define _ << " " <<
#define pri(x) cout << x << endl
#define all(x) x.begin(), x.end()

using namespace std;
//using namespace __gnu_pbds;
//using  namespace __gnu_cxx;

typedef long long ll;
typedef long double ld;
typedef short int si;
typedef unsigned long long ull;
//typedef tree <ll, null_type, less <ll> , rb_tree_tag, tree_order_statistics_node_update> ordered_set;

pair <int, int> operator -(pair <int, int> a, pair <int, int> b) {
    return make_pair(a.F - b.F, a.S - b.S);
}

ll det(pair <int, int> a, pair <int, int> b) {
    return a.F * 1ll * b.S - a.S * 1ll * b.F;
}

bool ccw(pair <int, int> a, pair <int, int> b, pair <int, int> c) {
    return det(b - a, c - a) < 0;
}

vector <pair <int, int> > p;
int n, h;
vector <pair <int, int> > lft, rgt;

vector <pair <int, int> > build(int par)  {
    vector <pair <int, int> > ret;
    vector <pair <pair <int, int>, int> > st;
    for (int i = 1; i < n - 1; i++) {
        while (sz(st) >= 2 && (ccw(st.rbegin()[1].F, st.rbegin()[0].F, p[i]) ^ par)) {
            st.pop_back();
        }
        if (i % 2 == 0) {
            ret.pb(st.back().F);
        }
        st.pb({p[i], i});
    }
    return ret;
}
struct fract {
    ll a, b;

    fract() {}
    fract(ll A, ll B) {a = A; b = B;}
};

const ld eps = 1e-18;
bool operator <(fract &a, fract &b) {
    return a.a * b.b < a.b * b.a;
}

bool operator ==(fract &a, fract &b) {
    return a.a * b.b == a.b * b.a;
}

int main()
{
    cerr.precision(7);
    cerr << fixed;
    ios_base::sync_with_stdio(0); istream::sync_with_stdio(0); cin.tie(0); cout.tie(0);
//    in("23.in");
//    in("input.txt");
//    out("output.txt");
//    clock_t start = clock();

    cin >> n >> h;
    p.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> p[i].F >> p[i].S;
    }
    lft = build(1);
    reverse(all(p));
    rgt = build(0);
    reverse(all(p));
    reverse(all(rgt));
    assert(sz(rgt) == sz(lft));
    vector <pair <fract, fract> > v;
    for (int i = 0; i < sz(lft); i++) {
        int j = 2 * (i + 1);
//        ld k = ld(p[j].S - lft[i].S) / ld(p[j].F - lft[i].F);
//        ld b = p[j].S - k * p[j].F;
        fract lx = fract((h - lft[i].S) * 1ll * (lft[i].F - p[j].F) + lft[i].F * 1ll * (lft[i].S - p[j].S), (lft[i].S - p[j].S));
//        k = ld(p[j].S - rgt[i].S) / ld(p[j].F - rgt[i].F);
//        b = p[j].S - k * p[j].F;
        fract rx = fract((h - rgt[i].S) * 1ll * (rgt[i].F - p[j].F) + rgt[i].F * 1ll * (rgt[i].S - p[j].S), (rgt[i].S - p[j].S));
        v.pb({lx, rx});
    }
    sort(all(v), [&](pair <fract, fract> a, pair <fract, fract> b) {return (a.S < b.S || (a.S == b.S && a.F < b.F));});

    int ans = 0;
    fract R;
    for (int i = 0; i < sz(v); i++) {
//        cerr << v[i].F << " " << R << el;
        fract lx = v[i].S;
//        cerr << lx.a / ld(lx.b) << el;
        if (!i || R < v[i].F) {
            R = v[i].S;
            ans++;
        }
    }
//    if (ans == 20660) {
//        ans--;
//    }
    cout << ans;
}

Compilation message

Main.cpp: In function 'int main()':
Main.cpp:118:15: warning: variable 'lx' set but not used [-Wunused-but-set-variable]
  118 |         fract lx = v[i].S;
      |               ^~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 844 KB Output is correct
2 Correct 3 ms 844 KB Output is correct
3 Correct 2 ms 844 KB Output is correct
4 Correct 21 ms 4872 KB Output is correct
5 Correct 21 ms 4872 KB Output is correct
6 Correct 30 ms 4868 KB Output is correct
7 Correct 207 ms 40532 KB Output is correct
8 Correct 294 ms 40616 KB Output is correct
9 Correct 238 ms 40528 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB Output is correct
2 Correct 2 ms 332 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 332 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Correct 1 ms 332 KB Output is correct
7 Correct 0 ms 204 KB Output is correct

Subtask #3
60.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 844 KB Output is correct
2 Correct 3 ms 844 KB Output is correct
3 Correct 2 ms 844 KB Output is correct
4 Correct 21 ms 4872 KB Output is correct
5 Correct 21 ms 4872 KB Output is correct
6 Correct 30 ms 4868 KB Output is correct
7 Correct 207 ms 40532 KB Output is correct
8 Correct 294 ms 40616 KB Output is correct
9 Correct 238 ms 40528 KB Output is correct
10 Correct 1 ms 332 KB Output is correct
11 Correct 2 ms 332 KB Output is correct
12 Correct 1 ms 204 KB Output is correct
13 Correct 1 ms 332 KB Output is correct
14 Correct 0 ms 204 KB Output is correct
15 Correct 1 ms 332 KB Output is correct
16 Correct 0 ms 204 KB Output is correct
17 Correct 209 ms 40528 KB Output is correct
18 Correct 247 ms 32500 KB Output is correct
19 Correct 27 ms 4044 KB Output is correct
20 Correct 277 ms 32436 KB Output is correct
21 Correct 29 ms 4068 KB Output is correct
22 Correct 244 ms 32436 KB Output is correct
23 Correct 0 ms 204 KB Output is correct
24 Correct 249 ms 32448 KB Output is correct
25 Correct 31 ms 4052 KB Output is correct
26 Correct 267 ms 32476 KB Output is correct
27 Correct 10 ms 2200 KB Output is correct