提出 #8568944

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ソースコード 拡げる

#include <bits/stdc++.h>
using namespace std;
#define _MACRO(_1, _2, _3, NAME, ...) NAME
#define _repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define _rep(i,n) _repl(i,0,n)
#define rep(...) _MACRO(__VA_ARGS__, _repl, _rep)(__VA_ARGS__)
#define pb push_back
#define all(x) begin(x),end(x)
#define uniq(x) sort(all(x)),(x).erase(unique(all(x)),end(x))
#ifdef LOCAL
#define dbg(...) _dbg(#__VA_ARGS__, __VA_ARGS__)
void _dbg(string){cerr<<endl;}
template<class H,class... T> void _dbg(string s,H h,T... t){int l=s.find(',');cerr<<s.substr(0,l)<<" = "<<h<<", ";_dbg(s.substr(l+1),t...);}
template<class T,class U> ostream& operator<<(ostream &o, const pair<T,U> &p){o<<"("<<p.first<<","<<p.second<<")";return o;}
template<class T> ostream& operator<<(ostream &o, const vector<T> &v){o<<"[";for(T t:v){o<<t<<",";}o<<"]";return o;}
#else
#define dbg(...) {}
#endif

int main(){
  int n;
  cin>>n;
  vector<pair<int,int>> v;
  rep(i,n) {
    int x,y;
    cin>>x>>y;
    if(x != 0 || y != 0) v.pb({x,y});
  }

  sort(all(v), [](auto &l, auto &r){
    auto m = [](pair<int,int> &p){
      using PID = pair<int, double>;
      if(p.first == 0){
        if(p.second > 0) return PID{0, p.second};
        else return PID{2, p.second};
      }
      else if (p.first > 0) return PID{1, -(double)p.second/p.first};
      else return PID{3, -(double)p.second/p.first};
    };
    return m(l) < m(r);
  });

  int m = v.size();
  rep(i,m) v.pb(v[i]);

  double ans =  0;
  rep(i,m) {
    long dx  = 0, dy = 0;
    rep(j, m) {
      dx += v[i+j].first;
      dy += v[i+j].second;
      ans = max(ans, sqrt(dx*dx + dy*dy));
    }
  }

  printf("%.10f\n", ans);

  return 0;
}

提出情報

ジャッジ結果