Submission #1214643

#	Time	Username	Problem	Language	Result	Execution time	Memory
1214643		DangKhoizzzz	Split the sequence (APIO14_sequence)	C++17	71 / 100	473 ms	196608 KiB

sequence

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#define ll long long
#define pii pair <ll , ll>
#define fi first
#define se second

using namespace std;

const ll INF = 1e18;
const int maxn = 1e5 + 2;
const int maxk = 2e2 + 2;

struct line
{
    ll a , b , p , trace;
    bool operator < (line o) {return a < o.a;}
    bool operator < (int k) {return p < k;}
};

struct Convex_Hull_Trick
{
    ll div(ll a , ll b)
    {
        return a/b - ((a^b) < 0 && a%b);
    }
    void isect(line &l , line y)
    {
        if(l.a == y.a) l.p = (l.b > y.b)? INF : -INF;
        else l.p = div(y.b - l.b , l.a - y.a);
    }

    vector <line> x; 

    void add(line l)
    {
        if(!x.empty()) isect(x.back() , l);
        while(x.size() > 1 && x[x.size()-2].p >= x.back().p)
        {
            x.pop_back();
            isect(x.back() , l);
        }
        x.push_back(l);
    }

    pii query(int v)
    {
        line l = *lower_bound(x.begin() , x.end() , v);
        return (pii){v*l.a + l.b  , l.trace};
    }
} cht[maxk];

int n , k , a[maxn];
ll pre[maxn] , suf[maxn];
int path[maxn][maxk];

void solve()
{
    cin >> n >> k; k++;
    for(int i = 1; i <= n; i++)
    {
        cin >> a[i];
        pre[i] = pre[i-1] + a[i];
    }
    for(int i = n; i >= 1; i--)
    {
        suf[i] = suf[i+1] + a[i];
    }

    cht[0].add({0 , 0 , INF , 0});

    ll ans = 0;

    for(int i = 1; i <= n; i++)
    {
        for(int z = min(i , k); z >= 1; z--)
        {
            pii tmp = cht[z-1].query(-suf[i+1]);
            ll dp = tmp.fi + pre[i]*suf[i+1];
            path[i][z] = tmp.se;
            cht[z].add({pre[i] , dp , INF , i});
            if(i == n && z == k) ans = dp;
        }
    }

    cout << ans << '\n';

    vector <int> qq;

    int curi = n;
    int curk = k;

    while(curk > 1)
    {
        curi = path[curi][curk];
        curk--;
        qq.push_back(curi);
    }

    reverse(qq.begin() , qq.end());
    for(int x: qq) cout << x << ' ';
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    //freopen("inp.txt" , "r" , stdin);
    //freopen("out.txt" , "w" , stdout);
    solve();
    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