#953339 (C++23) No.5020 Averaging

• 問題: No.5020 Averaging
• ユーザー: butsurizuki
• 提出日時: 2024-02-20 18:30:46
• 言語: C++23 (gcc 12.3.0 + boost 1.83.0)
• 結果: AC
• 実行時間: 5 ms / 1,000 ms
• コード長: 4,586 bytes
• コンパイル時間: 4,565 ms
• コンパイル使用メモリ: 289,496 KB
• 実行使用メモリ: 6,676 KB
• スコア: 68,055,930
• 最終ジャッジ日時: 2024-02-25 12:47:09
• 合計ジャッジ時間: 6,364 ms
• ジャッジサーバーID （参考情報）: judge14 / judge13

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	4 ms; 6,676 KB
testcase_01	AC	4 ms; 6,676 KB
testcase_02	AC	4 ms; 6,676 KB
testcase_03	AC	4 ms; 6,676 KB
testcase_04	AC	4 ms; 6,676 KB
testcase_05	AC	4 ms; 6,676 KB
testcase_06	AC	4 ms; 6,676 KB
testcase_07	AC	4 ms; 6,676 KB
testcase_08	AC	4 ms; 6,676 KB
testcase_09	AC	4 ms; 6,676 KB
testcase_10	AC	4 ms; 6,676 KB
testcase_11	AC	5 ms; 6,676 KB
testcase_12	AC	4 ms; 6,676 KB
testcase_13	AC	4 ms; 6,676 KB
testcase_14	AC	4 ms; 6,676 KB
testcase_15	AC	4 ms; 6,676 KB
testcase_16	AC	5 ms; 6,676 KB
testcase_17	AC	4 ms; 6,676 KB
testcase_18	AC	4 ms; 6,676 KB
testcase_19	AC	4 ms; 6,676 KB
testcase_20	AC	4 ms; 6,676 KB
testcase_21	AC	5 ms; 6,676 KB
testcase_22	AC	4 ms; 6,676 KB
testcase_23	AC	4 ms; 6,676 KB
testcase_24	AC	4 ms; 6,676 KB
testcase_25	AC	4 ms; 6,676 KB
testcase_26	AC	4 ms; 6,676 KB
testcase_27	AC	4 ms; 6,676 KB
testcase_28	AC	4 ms; 6,676 KB
testcase_29	AC	4 ms; 6,676 KB
testcase_30	AC	4 ms; 6,676 KB
testcase_31	AC	4 ms; 6,676 KB
testcase_32	AC	4 ms; 6,676 KB
testcase_33	AC	4 ms; 6,676 KB
testcase_34	AC	4 ms; 6,676 KB
testcase_35	AC	4 ms; 6,676 KB
testcase_36	AC	4 ms; 6,676 KB
testcase_37	AC	4 ms; 6,676 KB
testcase_38	AC	4 ms; 6,676 KB
testcase_39	AC	4 ms; 6,676 KB
testcase_40	AC	4 ms; 6,676 KB
testcase_41	AC	4 ms; 6,676 KB
testcase_42	AC	4 ms; 6,676 KB
testcase_43	AC	4 ms; 6,676 KB
testcase_44	AC	4 ms; 6,676 KB
testcase_45	AC	5 ms; 6,676 KB
testcase_46	AC	4 ms; 6,676 KB
testcase_47	AC	4 ms; 6,676 KB
testcase_48	AC	4 ms; 6,676 KB
testcase_49	AC	4 ms; 6,676 KB

コンパイルメッセージ

main.cpp: In function 'int main()':
main.cpp:140:23: warning: 'y' may be used uninitialized [-Wmaybe-uninitialized]
  140 |     p128 pp=f(p[x],p[y]);
      |                       ^
main.cpp:126:11: note: 'y' was declared here
  126 |     int x,y;
      |           ^
main.cpp:140:18: warning: 'x' may be used uninitialized [-Wmaybe-uninitialized]
  140 |     p128 pp=f(p[x],p[y]);
      |                  ^
main.cpp:126:9: note: 'x' was declared here
  126 |     int x,y;
      |         ^

ソースコード

#pragma GCC target("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include<bits/stdc++.h>
#include <sys/time.h>

using namespace std;

long long start_time;

void start_clock(){
  struct timeval tv;
  gettimeofday(&tv, NULL);
  start_time=(tv.tv_sec*1000000+tv.tv_usec);
}

long long current_clock(){
  struct timeval tv;
  gettimeofday(&tv, NULL);
  long long current_time=(tv.tv_sec*1000000+tv.tv_usec);
  // cout << current_time-start_time << "(us)\n";
  return current_time-start_time;
}

unsigned long long xor128(){
  static unsigned long long x=123456789,y=362436069,z=521288629,w=88675123;
  unsigned long long t;
  t=(x^(x<<11));x=y;y=z;z=w; return( w=(w^(w>>19))^(t^(t>>8)) );
}

using p128=pair<__int128,__int128>;
using i128=__int128;

vector<p128> convex_hull(vector<p128> P){
    // Copyright (c) 2023 0214sh7
    // https://github.com/0214sh7/library/
    if(P.size()<=2){
        return P;
    }
    vector<p128> H,L,R;
    sort(P.begin(),P.end());

    //下半分
    for(int i=0;i<P.size();i++){
        int j=L.size();
        while(j>=2 && (L[j-1].first-L[j-2].first)*(P[i].second-L[j-2].second)<=(L[j-1].second-L[j-2].second)*(P[i].first-L[j-2].first)){
            L.pop_back();
            j--;
        }
        L.push_back(P[i]);
    }

    //上半分
    for(int i=P.size()-1;i>=0;i--){
        int j=H.size();
        while(j>=2 && (H[j-1].first-H[j-2].first)*(P[i].second-H[j-2].second)<=(H[j-1].second-H[j-2].second)*(P[i].first-H[j-2].first)){
            H.pop_back();
            j--;
        }
        H.push_back(P[i]);
    }

    R=L;
    for(int i=1;i<H.size()-1;i++){
        R.push_back(H[i]);
    }

    return R;
}

p128 f(p128 a,p128 b){
  return {(a.first+b.first)/2,(a.second+b.second)/2};
}

i128 target=500000000000000000;

bool jud(vector<p128> &P){
  int n=P.size();
  for(int i=0;i<n;i++){
    i128 a=P[(i+1)%n].first-P[i].first;
    i128 b=P[(i+1)%n].second-P[i].second;
    i128 c=target-P[i].first;
    i128 d=target-P[i].second;

    if(a*d-b*c < 0){
      return false;
    }
  }
  return true;
}

void shrink(int tg,vector<p128> &p){
  for(int i=1;i<p.size();i++){
    p[i]=f(p[i],p[tg]);
  }
}

void simu(vector<int> &op,vector<p128> &p){
  for(auto &nx : op){
    p[0]=f(p[0],p[nx]);
    p[nx]=p[0];
  }
}

long long eval(p128 x){
  return max(x.first-target,x.second-target);
}

int main(){
  start_clock();
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int n;
  cin >> n;
  vector<p128> p(n);
  for(int i=0;i<n;i++){
    long long x,y;
    cin >> x >> y;
    p[i].first=x;
    p[i].second=y;
  }

  vector<pair<int,int>> pfx;
  for(int tr=0;tr<6;tr++){
    int x,y;
    i128 md=1e37;
    for(int i=0;i<n;i++){
      for(int j=i+1;j<n;j++){
        if(p[i]==p[j]){continue;}
        p128 pp=f(p[i],p[j]);
        i128 cd=(pp.first-target)*(pp.first-target)+(pp.second-target)*(pp.second-target);
        if(md>cd){
          md=cd;
          x=i;
          y=j;
        }
      }
    }
    p128 pp=f(p[x],p[y]);
    p[x]=pp;
    p[y]=pp;
    pfx.push_back({x,y});
  }

  // cout << "\n";
  // for(auto &nx : p){
  //  long long ox=nx.first;
  //  long long oy=nx.second;
  //  cout << ox << " " << oy << "\n";
  // }

  vector<int> res;
  vector<int> trash(n,0);
  trash[0]=1;
  vector<p128> cp=p;
  for(int hd=0;hd<50;hd++){
    int tg=-1;
    i128 gp=1e37;
    for(int i=1;i<n;i++){
      if(trash[i]){continue;}
      vector<p128> up=cp;
      shrink(i,up);
      vector<p128> htg;
      for(int j=1;j<n;j++){
        if(trash[j] || i==j){continue;}
        htg.push_back(up[j]);
      }
      vector<p128> ch=convex_hull(htg);
      if(jud(ch)){
        i128 gx=0,gy=0;
        for(auto &nx : ch){
          gx+=nx.first;
          gy+=nx.second;
        }
        gx/=ch.size();
        gy/=ch.size();
        i128 gd=(gx-target)*(gx-target)+(gy-target)*(gy-target);
        if(gp > gd){
          gp=gd;
          tg=i;
        }
      }
    }
    if(tg==-1){break;}
    shrink(tg,cp);
    // cout << hd << " : ";
    // for(auto &nx : cp){
    //   long long ox=nx.first;
    //   long long oy=nx.second;
    //   cout << ox << " " << oy << "\n";
    // }
    res.push_back(tg);
    trash[tg]=1;
  }
  reverse(res.begin(),res.end());

  cout << pfx.size()+res.size() << "\n";
  for(auto &nx : pfx){
    cout << nx.first+1 << " " << nx.second+1 << "\n";
  }
  for(auto &nx : res){
    cout << 1 << " " << nx+1 << "\n";
  }

  // simu(res,p);
  // for(auto &nx : p){
  //  long long ox=nx.first;
  //  long long oy=nx.second;
  //  cout << ox << " " << oy << "\n";
  // }
  return 0;
}