Submission #1127091

#	Time	Username	Problem	Language	Result	Execution time	Memory
1127091		Requiem	Fence (CEOI08_fence)	C++20	100 / 100	2 ms	324 KiB

fence

#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define fast ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#define MOD 1000000007
#define inf 1e18
#define fi first
#define se second
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define FORD(i,a,b) for(int i=a;i>=b;i--)
#define sz(a) ((int)(a).size())
#define endl '\n'
#define pi 3.14159265359
#define TASKNAME "fence"
using namespace std;
template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }
typedef pair<int,int> ii;
typedef pair<int,ii> iii;
typedef vector<int> vi;
const int MAXN = 102;
int dist[MAXN][MAXN];
const int costFence = 20;
const int costTree = 111;

struct point{
    int x, y;
    point(int _x = 0, int _y = 0){
        x = _x;
        y = _y;
    }

    point operator + (const point &other){
        return point(x + other.x, y + other.y);
    }

    point operator - (const point &other){
        return point(x - other.x, y - other.y);
    }
    bool operator < (const point &other) const{
        return (x == other.x) ? (y < other.y) : (x < other.x);
    }
};
int ccw(point a, point b, point c){
    b = b - a;
    c = c - a;
    int val = b.x * c.y - c.x * b.y;
    if (val < 0) return -1;
    if (val > 0) return 1;
    return 0;
}

vector<point> buildConvexHull(vector<point> polygon){
    sort(polygon.begin(), polygon.end());
    if (polygon.size() == 2) return polygon;

    point p0 = polygon[0];
    point p1 = polygon.back();

    vector<point> upper;
    vector<point> lower;
    vector<point> convexhull;

    upper.pb(p0);
    lower.pb(p0);

    FOR(i, 1, (int) polygon.size() - 1){
        if (i == polygon.size() - 1 or ccw(p0, polygon[i], p1) < 0){
            while(upper.size() > 1 and ccw(upper[upper.size() - 2], upper.back(), polygon[i]) >= 0) upper.pop_back();
            upper.pb(polygon[i]);
        }

        if (i == polygon.size() - 1 or ccw(p0, polygon[i], p1) > 0){
            while(lower.size() > 1 and ccw(lower[lower.size() - 2], lower.back(), polygon[i]) <= 0) lower.pop_back();
            lower.pb(polygon[i]);
        }
    }

    FOR(i, 0, (int) upper.size() - 1){
        convexhull.pb(upper[i]);
    }
    FORD(i, (int) lower.size() - 2, 1){
        convexhull.pb(lower[i]);
    }
    return convexhull;
}


vector<point> holes, trees, filtered, CH;

int n, m;

bool insidePolygon(vector<point> p, point pt){
    if (p.size() == 1){
        return false;
    }

    if (ccw(p[0], p[1], pt) == 0) return true;

    FOR(i, 1, (int) p.size() - 1){
        point p1 = p[i];
        point p2 = p[(i + 1) % p.size()];
        if (ccw(p1, p2, pt) == 0) return true;
        if (ccw(p1, p2, pt) != ccw(p[0], p[1], pt)) return false;
    }
    return true;
}

main()
{
    fast;
    if (fopen(TASKNAME".inp","r")){
        freopen(TASKNAME".inp","r",stdin);
        freopen(TASKNAME".out","w",stdout);
    }
    cin >> n >> m;
    FOR(i, 1, n){
        int x, y;
        cin >> x >> y;
        holes.pb(point(x, y));
    }
    FOR(i, 1, m){
        int x, y;
        cin >> x >> y;
        trees.pb(point(x, y));
    }

    CH = buildConvexHull(holes);
    int cons = 0, ans = inf;

    FOR(i, 0, m - 1){
        if (insidePolygon(CH, trees[i])) filtered.pb(trees[i]);
        else cons+= costTree;
    }


    memset(dist, 0x3f, sizeof(dist));

    FOR(i, 0, n - 1){
        FOR(j, 0, n - 1){

            if (i == j) continue;
            bool ch = true;
            FOR(k, 0, (int) filtered.size() - 1){
                if (ccw(holes[i], holes[j], filtered[k]) < 0) ch = false;
            }
            if (ch) {
                dist[i][j] = 1;
//                cout << i << ' ' << j << endl;
            }
        }
    }

    FOR(k, 0, n - 1){
        FOR(i, 0, n - 1){
            FOR(j, 0, n - 1){
                minimize(dist[i][j], dist[i][k] + dist[k][j]);
            }
        }
    }
    ans = m * costTree;

    FOR(i, 0, n - 1){
        if (dist[i][i] < inf) minimize(ans, cons + dist[i][i] * costFence);
    }
    cout << ans << endl;

}
/**
Warning:
Đọc sai đề???
Cận lmao
Code imple thiếu case nào không.
Limit.
**/

Compilation message (stderr)

fence.cpp:109:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  109 | main()
      | ^~~~
fence.cpp: In function 'int main()':
fence.cpp:113:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  113 |         freopen(TASKNAME".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
fence.cpp:114:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  114 |         freopen(TASKNAME".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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