Submission #678270

#	Time	Username	Problem	Language	Result	Execution time	Memory
678270		CodePlatina	Seesaw (JOI22_seesaw)	C++17	100 / 100	60 ms	10848 KiB

seesaw

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <tuple>
#include <iomanip>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define piii pair<int, pii>
#define plll pair<long long, pll>
#define tiii tuple<int, int, int>
#define tiiii tuple<int, int, int, int>
#define ff first
#define ss second
#define ee ss.ff
#define rr ss.ss
const int INF = (int)1e9 + 7;

using namespace std;

struct frac
{
    long long u, d;
    bool operator<(frac ot) const
    {
        return (__int128)u * ot.d < (__int128)ot.u * d;
    }
    operator long double() { return (long double)u / d; }
};

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int n; cin >> n;
    int A[n]; for(auto &i : A) cin >> i;
    long long ps[n + 1]{}; for(int i = 1; i <= n; ++i) ps[i] = ps[i - 1] + A[i - 1];

    pair<frac, frac> B[n];
    B[0] = { {ps[n], n}, {ps[n], n} };
    for(int i = 1; i < n; ++i)
    {
        int s = 0, e = i;
        while(s + 1 < e)
        {
            int mid = s + e >> 1;
            if(frac{ps[n - i + mid] - ps[mid], n - i} < frac{ps[n], n}) s = mid;
            else e = mid;
        }
        B[i] = { frac{ps[n - i + s] - ps[s], n - i}, frac{ps[n - i + s + 1] - ps[s + 1], n - i} };
    }

    sort(B, B + n);
    frac r = B[n - 1].ff;
    long double ans = r - B[0].ff;
    for(int i = 0; i < n - 1; ++i)
    {
        r = max(r, B[i].ss);
        ans = min(ans, r - B[i + 1].ff);
    }
    r = max(r, B[n - 1].ss);
    ans = min(ans, r - B[n - 1].ff);

    cout << fixed << setprecision(20) << ans;
}

Compilation message (stderr)

seesaw.cpp: In function 'int main()':
seesaw.cpp:47:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   47 |             int mid = s + e >> 1;
      |                       ~~^~~

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