結果

問題 No.96 圏外です。
ユーザー msm1993
提出日時 2020-11-18 16:34:08
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 111 ms / 5,000 ms
コード長 4,040 bytes
コンパイル時間 2,295 ms
コンパイル使用メモリ 189,352 KB
実行使用メモリ 11,552 KB
最終ジャッジ日時 2024-07-23 09:05:52
合計ジャッジ時間 5,170 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge5
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ファイルパターン 結果
other AC * 28
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ソースコード

diff #
プレゼンテーションモードにする

#include "bits/stdc++.h"
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
static const int INF = 0x3f3f3f3f; static const long long INFL = 0x3f3f3f3f3f3f3f3fLL;
typedef vector<int> vi; typedef pair<int, int> pii; typedef vector<pair<int, int> > vpii; typedef long long ll;
template<typename T, typename U> static void amin(T &x, U y) { if (y < x) x = y; }
template<typename T, typename U> static void amax(T &x, U y) { if (x < y) x = y; }
struct UnionFind {
    vector<int> data;
    void init(int n) { data.assign(n, -1); }
    bool unionSet(int x, int y) {
        x = root(x); y = root(y);
        if (x != y) {
            if (data[y] < data[x]) swap(x, y);
            data[x] += data[y]; data[y] = x;
        }
        return x != y;
    }
    bool findSet(int x, int y) { return root(x) == root(y); }
    int root(int x) { return data[x] < 0 ? x : data[x] = root(data[x]); }
    int size(int x) { return -data[root(x)]; }
};
struct P {
    typedef int T; typedef ll T2;   //T2は{a*b | a:T, b:T}を含むタイプ
    T x, y;
    P(T x_, T y_) : x(x_), y(y_) {}
    P() : x(0), y(0) {}
};
inline bool operator==(const P& a, const P& b) { return a.x == b.x && a.y == b.y; }
inline bool operator<(const P& a, const P& b) { return a.x < b.x || (a.x == b.x && a.y < b.y); }
inline P operator+(const P& a, const P& b) { return P(a.x + b.x, a.y + b.y); }
inline P operator-(const P& a, const P& b) { return P(a.x - b.x, a.y - b.y); }
inline P operator-=(P& a, const P& b) { a.x -= b.x, a.y -= b.y; return a; }
inline P::T2 cross(const P& a, const P& b) { return (P::T2)a.x*b.y - (P::T2)a.y*b.x; }
inline P::T2 dot(const P& a, const P& b) { return (P::T2)a.x*b.x + (P::T2)a.y*b.y; }
inline P::T2 norm(const P& a) { return (P::T2)a.x*a.x + (P::T2)a.y*a.y; }
ostream& operator<<(ostream& out, const P& x) { out << "(" << x.x << ", " << x.y << ")"; return out; }
inline int ccw(const P& a, const P& b, const P& c) {
    int ax = b.x - a.x, ay = b.y - a.y, bx = c.x - a.x, by = c.y - a.y;
    P::T2 t = (P::T2)ax*by - (P::T2)ay*bx;
    if (t > 0) return 1;
    if (t < 0) return -1;
    if ((P::T2)ax*bx + (P::T2)ay*by < 0) return +2;
    if ((P::T2)ax*ax + (P::T2)ay*ay < (P::T2)bx*bx + (P::T2)by*by) return -2;
    return 0;
}
vector<P> convex_hull(vector<P> ps) {
    if ((int)ps.size() <= 1) return ps;
    int n = ps.size(), k = 0;
    sort(ps.begin(), ps.end());
    vector<P> ch(2 * n);
    for (int i = 0; i < n; ch[k++] = ps[i++]) // lower-hull
        while (k >= 2 && ccw(ch[k - 2], ch[k - 1], ps[i]) <= 0) --k;
    for (int i = n - 2, t = k + 1; i >= 0; ch[k++] = ps[i--]) // upper-hull
        while (k >= t && ccw(ch[k - 2], ch[k - 1], ps[i]) <= 0) --k;
    ch.resize(k - 1);
    return ch;
}
int main() {
    int N;
    while (~scanf("%d", &N)) {
        vector<pair<int, int> > points(N);
        for (int i = 0; i < N; ++ i)
            scanf("%d%d", &points[i].first, &points[i].second);
        sort(points.begin(), points.end());
        const int D = 10, W = 10000, H = 10000;
        UnionFind uf;
        uf.init(N);
        {
            vector<vector<int>> ids(D + 1, vector<int>(H * 2 + 1, -1));
            auto get = [&](int x, int y) -> int& {
                x %= D + 1;
                if (x < 0) x += D + 1;
                return ids[x][y + H];
            };
            int pi = 0, qi = 0;
            rer(x, -W, W) {
                for (; qi != N && points[qi].first == x - D - 1; ++ qi)
                    get(x - D - 1, points[qi].second) = -1;
                for (; pi != N && points[pi].first == x; ++ pi) {
                    int y = points[pi].second;
                    rer(dx, -D, 0) {
                        rer(dy, -D, D) {
                            if (dx * dx + dy * dy > D * D || y + dy < -H || y + dy > H) continue;
                            int pj = get(x + dx, y + dy);
                            if (pj != -1)
                                uf.unionSet(pi, pj);
                        }
                    }
                    get(x, y) = pi;
                }
            }
        }
        vector<vector<P>> ccs(N);
        rep(i, N) ccs[uf.root(i)].emplace_back(points[i].first, points[i].second);
        double ans = 1;
        for (auto &cc : ccs) if(!cc.empty()) {
            cc = convex_hull(cc);
            ll maxd = 0;
            rep(i, cc.size()) rep(j, i) {
                amax(maxd, norm(cc[i] - cc[j]));
            }
            amax(ans, sqrt((double)maxd) + 2);
        }
        printf("%.10f\n", ans);
    }
    return 0;
}
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