結果
問題 | No.96 圏外です。 |
ユーザー |
|
提出日時 | 2014-11-06 02:40:15 |
言語 | C++11 (gcc 13.3.0) |
結果 |
AC
|
実行時間 | 314 ms / 5,000 ms |
コード長 | 3,826 bytes |
コンパイル時間 | 968 ms |
コンパイル使用メモリ | 86,564 KB |
実行使用メモリ | 193,264 KB |
最終ジャッジ日時 | 2024-12-24 07:39:05 |
合計ジャッジ時間 | 7,037 ms |
ジャッジサーバーID (参考情報) |
judge4 / judge2 |
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ファイルパターン | 結果 |
---|---|
other | AC * 28 |
ソースコード
#include <iostream>#include <vector>#include <complex>#include <queue>#include <algorithm>using namespace std;typedef complex<double> P;namespace std {bool operator < (const P& a, const P& b) {return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b);}}double cross(const P& a, const P& b) {return imag(conj(a)*b);}double dot(const P& a, const P& b) {return real(conj(a)*b);}int ccw(P a, P b, P c) {b -= a; c -= a;if (cross(b, c) > 0) return +1; // counter clockwiseif (cross(b, c) < 0) return -1; // clockwiseif (dot(b, c) < 0) return +2; // c--a--b on lineif (norm(b) < norm(c)) return -2; // a--b--c on linereturn 0;}vector<P> convex_hull(vector<P> ps) {int n = (int)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-hullwhile (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-hullwhile (k >= t && ccw(ch[k-2], ch[k-1], ps[i]) <= 0) --k;ch.resize(k-1);return ch;}double farthest(const vector<P>& v) {int n = (int)v.size();int si = 0, sj = 0;for(int t=0;t<n;t++){if (v[t].imag() < v[si].imag())si = t;if (v[t].imag() > v[sj].imag())sj = t;}double res = 0;int i = si, j = sj;do {res = max(res, abs(v[i]-v[j]));P di = v[(i+1)%n] - v[i];P dj = v[(j+1)%n] - v[j];if (cross(di, dj) >= 0)j = (j+1)%n;elsei = (i+1)%n;} while(!(i == si && j == sj));return res;}const int OFFSET = 10000;const int B = 11;int N;int X[122222], Y[122222];vector<int> bucket[2222][2222];vector<int> graph[122222];bool reachable(int i, int j){int dx = X[i] - X[j];int dy = Y[i] - Y[j];return (dx * dx + dy * dy <= 100);}bool used[122222];double solve(){double res = 0;for(int i=0;i<N;i++)if(!used[i]){vector<P> ps;ps.push_back(P(X[i], Y[i]));queue<int> Q;Q.push(i);used[i] = true;while(!Q.empty()){int v = Q.front(); Q.pop();for(int u : graph[v]){if(used[u])continue;used[u] = true;Q.push(u);ps.push_back(P(X[u], Y[u]));}}if(ps.size() <= 1)continue;if(ps.size() == 2){res = max(res, abs(ps[0] - ps[1]));continue;}vector<P> convex = convex_hull(ps);res = max(res, farthest(convex));}return res + 2;}int main(){cin >> N;if(N == 0){cout << 1 << endl;return 0;}for(int i=0;i<N;i++){cin >> X[i] >> Y[i];X[i] += OFFSET;Y[i] += OFFSET;}for(int i=0;i<N;i++){int ix = X[i] / B;int iy = Y[i] / B;bucket[ix][iy].push_back(i);}for(int i=0;i<N;i++){int ix = X[i] / B;int iy = Y[i] / B;for(int dx=-1;dx<=1;dx++)for(int dy=-1;dy<=1;dy++){int nx = ix + dx;int ny = iy + dy;if(nx < 0 || ny < 0)continue;for(int j : bucket[nx][ny]){if(j != i && reachable(i, j)){graph[i].push_back(j);}}}}printf("%.10f\n", solve());return 0;}