Submission #1058080

#	Time	Username	Problem	Language	Result	Execution time	Memory
1058080		codefox	Split the sequence (APIO14_sequence)	C++14	71 / 100	59 ms	131072 KiB

sequence

#include<bits/stdc++.h>

using namespace std;

#define ll long long

#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")

vector<vector<ll>> dp;
vector<ll> pref;

double inter2(int &i, int &j, int &k)
{
    return ((-pref[j]*pref[j]+dp[j][k])-(-pref[i]*pref[i]+dp[i][k]))/(double)(pref[i]-pref[j]);
}

ll inter(int &i, int &j, int k)
{
    return ((-pref[j]*pref[j]+dp[j][k])-(-pref[i]*pref[i]+dp[i][k]));
}

int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    //freopen("../input.txt", "r", stdin);
    //freopen("../output.txt", "w", stdout);

    int n, k;
    cin >> n >> k;
    k++;
    vector<deque<int>> ch(k+1);
    ch[0].push_back(0);

    pref.assign(n+1, 0);
    dp.assign(n+1, vector<ll>(k+1, 0));
    vector<vector<int>> best(n+1, vector<int>(k+1, -1));
    for (int i = 1; i <= n; i++)
    {
        int a;
        cin >> a;
        pref[i] = pref[i-1];
        pref[i]+=a;
        for(int j = min(k-1, i-1); j>= 0; j--)
        {
            while (ch[j].size()>1 && inter2(ch[j][0], ch[j][1], j)<=
            pref[i]) ch[j].pop_front();
            int h = ch[j].front();
            best[i][j+1] = h;
            dp[i][j+1] = dp[h][j]-pref[h]*(pref[h]-pref[i]);
            while (ch[j+1].size()>1 && 
            inter(ch[j+1][ch[j+1].size()-2], ch[j+1].back(), j+1)
            *(pref[ch[j+1].back()]-pref[i]) >= 
            inter(ch[j+1].back(), i, j+1)
            *(pref[ch[j+1][ch[j+1].size()-2]]-pref[ch[j+1].back()])) 
            ch[j+1].pop_back();
            ch[j+1].push_back(i);

        }
    }
    int cn = n;
    cout << dp[cn][k] << "\n";
    for (int i = k; i >= 2; i--)
    {
        cout << best[cn][i] << " ";
        cn = best[cn][i];
    }


    return 0;
}

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 0 / 29