Submission #801799

#	Time	Username	Problem	Language	Result	Execution time	Memory
801799		ymm	Seesaw (JOI22_seesaw)	C++17	34 / 100	1800 ms	384 KiB

seesaw

#include <bits/stdc++.h>
#define Loop(x,l,r) for (ll x = (l); x < (r); ++x)
typedef long long ll;
using namespace std;

mt19937_64 rd(time(0));
const int N = 200'010;
double pos[N];
double sum;
int n;

double solve(double l)
{
	double sum = ::sum;
	if (l > sum/n)
		return 1;
	int p0 = 0, p1 = n-1;
	double mn = sum/n, mx = sum/n;
	for (int cnt = n; p0 < p1; --cnt) {
		if (l <= (sum-pos[p1])/(cnt-1)) {
			sum -= pos[p1];
			mn = min(mn, sum/(cnt-1));
			--p1;
		} else {
			sum -= pos[p0];
			mx = max(mx, sum/(cnt-1));
			++p0;
		}
	}
	return mx - mn;
}

int main()
{
	cin.tie(0) -> sync_with_stdio(false);
	cin >> n;
	Loop (i,0,n) {
		ll x;
		cin >> x;
		pos[i] = (double)x/1e9;
		sum += pos[i];
	}
	double m = sum/n;
	double ans = m - pos[0];
	while (clock() < 1.8 * CLOCKS_PER_SEC) {
		double x = (double)rd()/ULONG_LONG_MAX * (m - pos[0]) + pos[0];
		ans = min(ans, solve(x));
	}
	cout << fixed << setprecision(9);
	cout << ans*1e9 << '\n';
}

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