Submission #446232

#	Time	Username	Problem	Language	Result	Execution time	Memory
446232		prvocislo	Fence (CEOI08_fence)	C++17	30 / 100	1 ms	332 KiB

fence

#include <bits/stdc++.h>
typedef long long ll;
using namespace std;

const int stlp = 20, strom = 111; 
void upd(int &a, const int &b) { a = min(a, b); }
struct bod { int x, y; };
int sign(int a) { return (a == 0 ? 0 : (a < 0 ? -1 : 1)); }
int area(bod a, bod b, bod c) // orientovany obsah uhlu <) abc
{
    a.x -= b.x, a.y -= b.y;
    c.x -= b.x, c.y -= b.y;
    return a.x * c.y - a.y * c.x;
}
bool inside_tri(const bod &a, const bod &b, const bod &c, const bod &i)
{
    int zab = sign(area(a, b, i)), zbc = sign(area(b, c, i)), zca = sign(area(c, a, i));
    return zab == zca && zca == zbc;
}
bool inside(const bod &a, const bod &b, const bod &c, const vector<bod> &v)
{
    for (const bod &i : v) if (inside_tri(a, b, c, i)) return true;
    return false;
}
bod o;
bool cmp(const bod &a, const bod &b)
{
    return area(a, o, b) < 0;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    vector<bod> f(n), s(m);
    int ans = m * strom, id = 0;
    for (int i = 0; i < n; i++) 
    {
        cin >> f[i].x >> f[i].y;
        if (f[i].x < f[id].x || (f[i].x == f[id].x && f[i].y < f[id].y)) id = i;
    }
    o = f[id]; swap(f[id], f[0]);
    sort(f.begin(), f.end(), cmp);
    vector<bod> ko;
    for (int i = 0; i < n; i++)
    {
        if (ko.size() >= 2 && area(ko[ko.size()-2], ko[ko.size()-1], f[i]) < 0) ko.pop_back();
        ko.push_back(f[i]);
    }
    int k = ko.size();
    for (int i = 0; i < k; i++) ko.push_back(ko[i]);
    int inside_ko = 0;
    for (int i = 0; i < m; i++)
    {
        cin >> s[i].x >> s[i].y;
        bool is_in = false;
        for (int j = 2; j < k; j++) is_in |= inside_tri(ko[0], ko[j-1], ko[j], s[i]);
        inside_ko += is_in;
    }
    vector<vector<bool> > ok(2*k, vector<bool>(2*k));
    for (int i = 0; i < 2*k-1; i++) 
    {
        ok[i][i] = ok[i][i+1] = true;
        for (int j = i+2; j < min(i+k, 2*k); j++) 
            if (ok[i][j-1] && !inside(ko[i], ko[j-1], ko[j], s)) 
                    ok[i][j] = true;
    }
    vector<vector<int> > dp(2*k, vector<int>(2*k, k+1));
    for (int i = 0; i < k; i++)
    {
        dp[i][i] = 0;
        for (int r1 = i; r1 < i + k; r1++) for (int r2 = r1+1; r2 <= i+k; r2++) if (ok[r1][r2])
            upd(dp[i][r2], dp[i][r1] + 1);
        upd(ans, dp[i][i+k]*stlp + (m - inside_ko)*strom);
    }
    cout << ans << "\n";
    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 10 / 10
• Subtask 6: 0 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10