Submission #1058107

#	Time	Username	Problem	Language	Result	Execution time	Memory
1058107		codefox	Split the sequence (APIO14_sequence)	C++14	33 / 100	17 ms	131072 KiB

sequence

#include<bits/stdc++.h>

using namespace std;

#define ll long long

const int N = 1e5+1;
const int K = 202;

ll dp[K][N];
ll pref[N];
int best[K][N];

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

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

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++;
    deque<int> ch[K];
    ch[0].push_back(0);

    pref[0] = 0;
    dp[0][0] =0;
    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[j+1][i] = h;
            dp[j+1][i] = dp[j][h]-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[k][cn] << "\n";
    for (int i = k; i >= 2; i--)
    {
        cout << best[i][cn] << " ";
        cn = best[i][cn];
    }


    return 0;
}

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