Submission #1221363

#	Time	Username	Problem	Language	Result	Execution time	Memory
1221363		juaquin_remon	Balloons (CEOI11_bal)	C++20	100 / 100	110 ms	1860 KiB

bal

#include<bits/stdc++.h>
#include <iomanip>

using namespace std;
 
typedef long long ll;
typedef vector<ll> vl;
typedef pair<ll,ll> pl;

#define forr(i,a,b) for(int i=int(a);i<int(b);++i)
#define forn(i,n) forr(i,0,n)
#define dforr(i,a,b) for(int i=int(b)-1;i>=int(a);--i)
#define dforn(i,n) dforr(i,0,n)
#define fore(e,c) for(const auto &e : (c))
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define fi first
#define se second

const ll MAXN = -1;
const ll mod = 1e9+7;
const ll inf = 1e18+10;
typedef long double ld;

struct Line {
	mutable ld k, m, p;
	bool operator<(const Line& o) const { return k < o.k; }
	bool operator<(ll x) const { return p < x; }
};

struct LineContainer : multiset<Line, less<>> {
	// (for doubles, use inf = 1/.0, div(a,b) = a/b)
	ld inf = 1/.0;
	ld div(ld a, ld b) { // floored division
		return a / b; }
	bool isect(iterator x, iterator y) {
		if (y == end()) return x->p = inf, 0;
		if (x->k == y->k) x->p = x->m > y->m ? inf : -inf;
		else x->p = div(y->m - x->m, x->k - y->k);
		return x->p >= y->p;
	}
	void add(ld k, ld m) {
		auto z = insert({k, m, 0}), y = z++, x = y;
		while (isect(y, z)) z = erase(z);
		if (x != begin() && isect(--x, y)) isect(x, y = erase(y));
		while ((y = x) != begin() && (--x)->p >= y->p)
			isect(x, erase(y));
	}
	ld query(ld x) {
		assert(!empty());
		auto l = *lower_bound(x);
		return l.k * x + l.m;
	}
};

void solve(){
  ll n; cin >> n;
  
  LineContainer lc;

  forn(i, n) {
    ll x, maxr;
    cin >> x >> maxr;
    cout << fixed << setprecision(3);
    ld r;
    if (i == 0) {
      cout << maxr << "\n";
      r = maxr;
    } else {
      ld sqrt_r_opt = -lc.query(x);
      ld r_opt = sqrt_r_opt*sqrt_r_opt;
      r = min((ld)maxr, r_opt);
      cout << r << "\n";
    }

    ld sqrt_r = sqrtl(r);
    lc.add(-1./(2*sqrt_r), x/(2*sqrt_r));
  }
}

int main(){
  ios::sync_with_stdio(0); cin.tie(0);
  int tt = 1;
  while(tt--) solve();
  return 0;
}

• 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