Submission #612399

#	Time	Username	Problem	Language	Result	Execution time	Memory
612399		balbit	Seesaw (JOI22_seesaw)	C++14	67 / 100	29 ms	8692 KiB

seesaw

#include <bits/stdc++.h>
using namespace std;

#define int ll
#define ll long long
#define pii pair<int, int>
#define f first
#define s second

#define REP(i,n) for (int i = 0; i<n; ++i)
#define REP1(i,n) for(int i = 1; i<=n; ++i)
#define MX(a,b) a = max(a,b)
#define MN(a,b) a = min(a,b)
#define pb push_back
#define SZ(x) (int)((x).size())
#define ALL(x) (x).begin(),(x).end()
#ifdef BALBIT
#define bug(...) cerr<<"#"<<__LINE__<<" "<<#__VA_ARGS__<<"- ", _do(__VA_ARGS__)
template<typename T> void _do(T && x) {cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T && x, S && ...y) {cerr<<x<<", "; _do(y...);}
#else
#define bug(...)
#define endl '\n'
#endif 

const ll inf = 0x3f3f3f3f3f3f3f3f;
const int maxn = 2e5+5;
int a[maxn], ps[maxn];

vector<ll> yoi;

signed main(){
	ios::sync_with_stdio(0), cin.tie(0);
	bug(1,2);

	int n; cin>>n;

	REP1(i,n) {
		cin>>a[i];
		ps[i] = ps[i-1] + a[i];
	}
	vector<pair<double, double> > po;

	double cen = ps[n] / (double)(n);
	double rbound = cen;

	{
		int x = 0;
		for (int i = n; i>=1;--i) {
			while (x+i<n && (ps[x+i]-ps[x]) * (__int128) n < ps[n] * i) {
				++x;
			}
			if (i == n) {
				po.pb({cen, inf});
			}else{
				assert(x>0);
				double prv = (ps[x+i-1] - ps[x-1])/(double)i;

				double ha = (ps[x+i] - ps[x])/(double)i;
				po.pb({prv, ha}); po.pb({ha, inf});
			}
		}

	}

	sort(ALL(po));
	double re = inf;
	for(auto yo : po) {
		MN(re,rbound - yo.f);
		MX(rbound, yo.s);
		if(rbound >= inf -1) break;
	}

	cout<<fixed<<setprecision(12)<<re<<endl;


}

• Subtask 1: 1 / 1
• Subtask 2: 33 / 33
• Subtask 3: 33 / 33
• Subtask 4: 0 / 33