Submission #382796

#	Time	Username	Problem	Language	Result	Execution time	Memory
382796		ne4eHbKa	Planine (COCI21_planine)	C++17	110 / 110	353 ms	37868 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#ifndef _LOCAL
//#pragma GCC optimize("O3,Ofast")
#else
#pragma GCC optimize("O0")
#endif
template<typename t> inline void umin(t &a, const t b) {a = min(a, b);}
template<typename t> inline void umax(t &a, const t b) {a = max(a, b);}
typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;
typedef int8_t byte;
ll time() {return chrono::system_clock().now().time_since_epoch().count();}
mt19937 rnd(time());
#define ft first
#define sd second
#define len(f) int((f).size())
#define bnd(f) (f).begin(), (f).end()
#define _ <<' '<<
const int inf = 1e9 + 5;
const ll inf64 = 4e18 + 5;
const int md = 998244353;
namespace MD {
    void add(int &a, const int b) {if((a += b) >= md) a -= md;}
    void sub(int &a, const int b) {if((a -= b) < 0) a += md;}
    int prod(const int a, const int b) {return ll(a) * b % md;}
};

const int N = 1e6 + 5;
int h, x[N], y[N], n;
vector<pair<ld, ld>> c;
vector<int> f;

ld point(int i, int j) { return x[j] + ld(x[j] - x[i]) / (y[j] - y[i]) * (h - y[j]); }

const ld eps = 1e-15;
inline bool eq(const ld a, const ld b) {return abs(a - b) < eps;}
inline bool le(const ld a, const ld b) {return a + eps < b;}

ll s(int a, int b, int c) { return (x[b] - x[a]) * ll(y[c] - y[a]) - (y[b] - y[a]) * ll(x[c] - x[a]); }

void solve() {
    cin >> n >> h;
    for(int i = 0; i < n; ++i)
        cin >> x[i] >> y[i];
    c.resize(n - 3 >> 1);
    int i = 0;
    for(int j = 0; j < n; ++j) {
        while(len(f) > 1) {
            int pr = f.back();
            int pr2 = f[len(f) - 2];
            if(s(pr2, pr, j) < 0)
                break;
            f.pop_back();
        }
        if(!(j & 1) && j && j + 1 < n)
            c[i++].ft = point(j, f.back());
        f.push_back(j);
    }
    i = len(c) - 1;
    for(int j = n - 1; ~j; --j) {
        while(len(f) > 1) {
            int pr = f.back();
            int pr2 = f[len(f) - 2];
            if(s(pr2, pr, j) > 0)
                break;
            f.pop_back();
        }
        if(!(j & 1) && j && j + 1 < n)
            c[i--].sd = point(j, f.back());
        f.push_back(j);
    }
    sort(bnd(c));
    n = len(c);
    for(int i = n - 2; i >= 0; --i)
        umin(c[i].sd, c[i + 1].sd);
    int ans {};
    bool u = true;
    ld z;
    for(int i = 0; i < n; ++i) {
        if(u || le(z, c[i].ft))
            z = c[i].sd,
            ++ans,
            u = false;
    }
    cout << ans << endl;
}

signed main() {
    ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#ifndef _LOCAL
//    freopen("file.in", "r", stdin);
//    freopen("file.out", "w", stdout);
#else
    system("color a");
    freopen("in.txt", "r", stdin);
    int t; cin >> t;
    while(t--)
#endif
    solve();
}

Compilation message (stderr)

Main.cpp: In function 'void solve()':
Main.cpp:47:16: warning: suggest parentheses around '-' inside '>>' [-Wparentheses]
   47 |     c.resize(n - 3 >> 1);
      |              ~~^~~

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60