Submission #802938

#	Time	Username	Problem	Language	Result	Execution time	Memory
802938		myst6	Seesaw (JOI22_seesaw)	C++14	34 / 100	2061 ms	156928 KiB

seesaw

#pragma GCC optimize("O2")

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main() {
    cin.tie(0)->sync_with_stdio(0);
    int N;
    cin >> N;
    vector<ll> A(N);
    for (int i=0; i<N; i++) cin >> A[i];
    double bary[N][N];
    set<double> baries;
    memset(bary, 0, sizeof bary);
    for (int i=0; i<N; i++) {
        ll sum = 0;
        for (int j=i; j<N; j++) {
            sum += A[j];
            bary[i][j] = (double)sum / (double)(j - i + 1);
            baries.insert(bary[i][j]);
        }
    }
    double ans = 1e9;
    double dp[N][N];
    cout << setprecision(100);
    for (double upper_bound : baries) {
        if (upper_bound < bary[0][N-1]) continue;
        memset(dp, 0, sizeof dp);
        for (int len=0; len<N; len++) {
            for (int i=0; i<N-len; i++) {
                if (len > 0) {
                    if (bary[i+1][i+len] <= upper_bound) {
                        dp[i][i+len] = min(bary[i][i+len], max(
                            dp[i+1][i+len],
                            dp[i][i+len-1]
                        ));
                    } else {
                        // if (abs(bary[i+1][i+len] - upper_bound) < 1)
                        //     cout << bary[i+1][i+len] << " >= " << upper_bound << "\n";
                        dp[i][i+len] = min(bary[i][i+len], dp[i][i+len-1]);
                    }
                } else {
                    dp[i][i+len] = bary[i][i+len];
                }
            }
        }
        // cout << upper_bound << ":\n";
        // for (int i=0; i<N; i++) {
        //     for (int j=0; j<N; j++) {
        //         cout << dp[i][j] << " ";
        //     }
        //     cout << "\n";
        // }
        // cout << "\n";
        ans = min(ans, upper_bound - dp[0][N-1]);
    }
    cout << ans << "\n";
    return 0;
}

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