oj.uz

Submission #854678

# Submission time Handle Problem Language Result Execution time Memory
854678 2023-09-28T13:44:39 Z boris_mihov Seesaw (JOI22_seesaw) C++17
0 / 100
 0 ms 348 KB 
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <numeric>
#include <cassert>
#include <vector>

typedef long long llong;
const int MAXN = 200000 + 10;
const int INF  = 1e9;

int n;
int a[MAXN];

int check2(long double l, long double r)
{
    llong sum = 0;
    for (int i = 1 ; i <= n ; ++i)
    {
        sum += a[i];
    }

    int lPtr = 1, rPtr = n;
    while (lPtr <= rPtr)
    {
        if (sum / (double)(rPtr - lPtr + 1) < l || sum / (double)(rPtr - lPtr + 1) > r)
        {
            return false;
        }

        if (lPtr == rPtr)
        {
            break;
        }
        
        if ((sum - a[rPtr]) / (double)(rPtr - lPtr) >= l)
        {
            sum -= a[rPtr];
            rPtr--;
        } else
        {
            sum -= a[lPtr];
            lPtr++;
        }
    }

    return true;
}

bool check(long double w)
{
    for (int i = 1 ; i <= n ; ++i)
    {
        llong sum = 0;
        for (int j = i ; j <= n ; ++j)
        {
            sum += a[j];
            if (check2(sum / (long double)(j - i + 1), sum / (long double)(j - i + 1) + w))
            {
                return true;
            }
        }
    }

    return false;
}

void solve()
{
    long double l = 0.0, r = INF, mid;
    for (int i = 0 ; i < 64 ; ++i)
    {
        mid = (l + r) / 2.0;
        if (!check(mid)) l = mid;
        else r = mid;
    }

    std::cout << std::fixed << std::setprecision(10) << r << '\n';
}

void input()
{
    std::cin >> n;
    for (int i = 1 ; i <= n ; ++i)
    {
        std::cin >> a[i];
    }
}

void fastIOI()
{
    std::ios_base :: sync_with_stdio(0);
    std::cout.tie(nullptr);
    std::cin.tie(nullptr);
}

int main()
{
    fastIOI();
    input();
    solve();

    return 0;
}

Subtask #1
0 / 1.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Incorrect 0 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Incorrect 0 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Incorrect 0 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Incorrect 0 ms 348 KB Output isn't correct
3 Halted 0 ms 0 KB -