oj.uz

Submission #513829

# Submission time Handle Problem Language Result Execution time Memory
513829 2022-01-17T16:58:34 Z kartel Planine (COCI21_planine) C++14
110 / 110
 291 ms 41212 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 (ld)a.a * ld(b.b) < (ld)a.b * ld(b.a);
}

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

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 3 ms 972 KB Output is correct
2 Correct 4 ms 960 KB Output is correct
3 Correct 3 ms 996 KB Output is correct
4 Correct 25 ms 5356 KB Output is correct
5 Correct 24 ms 5640 KB Output is correct
6 Correct 27 ms 5620 KB Output is correct
7 Correct 255 ms 41128 KB Output is correct
8 Correct 245 ms 41184 KB Output is correct
9 Correct 252 ms 41156 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 320 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 300 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 332 KB Output is correct
7 Correct 1 ms 332 KB Output is correct

Subtask #3
60.0 / 60.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 972 KB Output is correct
2 Correct 4 ms 960 KB Output is correct
3 Correct 3 ms 996 KB Output is correct
4 Correct 25 ms 5356 KB Output is correct
5 Correct 24 ms 5640 KB Output is correct
6 Correct 27 ms 5620 KB Output is correct
7 Correct 255 ms 41128 KB Output is correct
8 Correct 245 ms 41184 KB Output is correct
9 Correct 252 ms 41156 KB Output is correct
10 Correct 1 ms 320 KB Output is correct
11 Correct 1 ms 332 KB Output is correct
12 Correct 1 ms 204 KB Output is correct
13 Correct 1 ms 300 KB Output is correct
14 Correct 1 ms 204 KB Output is correct
15 Correct 1 ms 332 KB Output is correct
16 Correct 1 ms 332 KB Output is correct
17 Correct 260 ms 41212 KB Output is correct
18 Correct 261 ms 33096 KB Output is correct
19 Correct 26 ms 4684 KB Output is correct
20 Correct 254 ms 33072 KB Output is correct
21 Correct 39 ms 4676 KB Output is correct
22 Correct 220 ms 33132 KB Output is correct
23 Correct 0 ms 204 KB Output is correct
24 Correct 235 ms 33076 KB Output is correct
25 Correct 24 ms 4724 KB Output is correct
26 Correct 291 ms 33084 KB Output is correct
27 Correct 18 ms 2716 KB Output is correct