Submission #801744

#	Time	Username	Problem	Language	Result	Execution time	Memory
801744		Sohsoh84	Seesaw (JOI22_seesaw)	C++17	0 / 100	1 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;

inline ld calc(int l, int r) {
	ll s = 0;
	for (int i = l; i <= r; i++)
		s += A[i];

	return ld(s) / (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];
	
	ld L = calc(1, n), R = A[n];
	for (int t = 0; t <= 400 && L <= R; t++) {
		ld mid1 = L + (R - L) / 3;
		ld mid2 = R - (R - L) / 3;

		if (solve(mid1) <= solve(mid2)) R = mid2;
		else L = mid1;
	}

	cout << setprecision(12) << fixed << solve(L) << endl;
	return 0;
}

Compilation message (stderr)

seesaw.cpp: In function 'ld solve(ld)':
seesaw.cpp:33:6: warning: unused variable 'tll' [-Wunused-variable]
   33 |   ld tll = min(tl, calc(l + 1, r)), tlr = max(tr, calc(l + 1, r));
      |      ^~~

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