Submission #802205

#	Time	Username	Problem	Language	Result	Execution time	Memory
802205		Sohsoh84	Seesaw (JOI22_seesaw)	C++17	1 / 100	2 ms	212 KiB

seesaw

// Wounds should become scars but I'm cracked instead U+1FAE0
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll, ll> pll;
typedef long double ld;

#define all(x)			(x).begin(),(x).end()
#define X			first
#define Y			second
#define sep			' '
#define endl			'\n'
#define debug(x)		cerr << #x << ": " <<  x << endl;

const ll MAXN = 1e6 + 10;

int A[MAXN], n;
ll ps[MAXN];

inline ld calc(int l, int r) {

	return ld(ps[r] - ps[l - 1]) / (r - l + 1);
}

inline ld solve(ld max_r) {	
	int l = 1, r = n;
	ld tl = calc(l, r), tr = calc(l, r);
	while (l < r) {
		ld tll = min(tl, calc(l + 1, r)), tlr = max(tr, calc(l + 1, r));
		if (tlr <= max_r) l++;
		else r--;

		tl = min(tl, calc(l, r));
		tr = max(tr, calc(l, r));
	}

	return tr - tl;
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> A[i];
		ps[i] = ps[i - 1] + A[i];
	}

	ld ans = A[n] - A[1];
	for (int l = 1; l <= n; l++) {
		for (int r = n; r >= max(l, n - 20); r--) {
			ans = min(ans, solve(calc(l, r)));
		}
	}

	cout << setprecision(10) << fixed << ans << endl;
	return 0;
}

Compilation message (stderr)

seesaw.cpp: In function 'ld solve(ld)':
seesaw.cpp:31:6: warning: unused variable 'tll' [-Wunused-variable]
   31 |   ld tll = min(tl, calc(l + 1, r)), tlr = max(tr, calc(l + 1, r));
      |      ^~~

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