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Submission #698358

# Submission time Handle Problem Language Result Execution time Memory
698358 2023-02-13T09:28:13 Z Duy_e Seesaw (JOI22_seesaw) C++14
0 / 100
 1 ms 212 KB 
#include <bits/stdc++.h>
#define ll long long
#define pii pair <ll, ll>
#define st first
#define nd second
#define rep(i, n, m) for (ll i = n; i <= m; i ++)
#define rrep(i, n, m) for (ll i = n; i >= m; i --)
#define file "test"
using namespace std;

const long long N = 2e5 + 7;
const long long INF = 1e18;
const long long MOD = 2e9 + 11;
const long long base = 311;
const long double eps = 1e-10;
ll n, a[N];

bool is_smaller(pii x, pii y) {
    return x.st * y.nd <= x.nd * y.st;
}

long double checkL(int l, int r, int n) {
    ll s = 0;
    rep(i, 1, n) s += a[i];
    pii pivot = {s, n};
    pii ans = {s, n};
    while (l < r) {
        if (is_smaller(pii(s - a[l], n - 1), pivot)) {
            s -= a[l]; n --; l ++;
            if (is_smaller(pii(s, n), ans))
                ans = pii(s, n);
            continue;
        }
        s -= a[r]; n --; r --;
        if (is_smaller(pii(s, n), ans))
            ans = pii(s, n);
    }

    long double x = -ans.st * pivot.nd + ans.nd * pivot.st, y = pivot.nd * ans.nd;
    return x / y;
}

long double checkR(int l, int r, int n) {
    ll s = 0;
    rep(i, 1, n) s += a[i];
    pii pivot = {s, n};
    pii ans = {s, n};
    while (l < r) {
        if (is_smaller(pivot, pii(s - a[r], n - 1))) {
            s -= a[r]; n --; r --;
            if (is_smaller(ans, pii(s, n)))
                ans = pii(s, n);
            continue;
        }
        s -= a[l]; n --; l ++;
        if (is_smaller(ans, pii(s, n)))
            ans = pii(s, n);
    }
    long double x = ans.st * pivot.nd - ans.nd * pivot.st, y = pivot.nd * ans.nd;
    // << "R: " << x << ' ' << y << '\n';
    return x / y;
}

int main() {

    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    #ifndef ONLINE_JUDGE
       // freopen(file".inp", "r", stdin);
       // freopen(file".out", "w", stdout);
    #endif // ONLINE_JUDGE

    cin >> n;
    rep(i, 1, n)
        cin >> a[i];
    cout << setprecision(10) << fixed << min(checkL(1, n, n), checkR(1, n, n));

    return 0;
}

Subtask #1
0 / 1.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -