Submission #1215285

#	Time	Username	Problem	Language	Result	Execution time	Memory
1215285		cpdreamer	Split the sequence (APIO14_sequence)	C++17	71 / 100	421 ms	196608 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e17;
typedef long long ll;
const ll MOD = (ll)1e9+7;
#define P pair
#define S second
#define F first
#define pb push_back
#define V vector
#define all(v) v.begin(), v.end()

void file() {
    freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);
}
struct li_chao {
private:
    struct line {
        ll m,p;
        ll evaluate(ll x) {
            return m*x+p;
        }
        line(ll _m=0,ll _p=-1e18):m(_m),p(_p){}
    };
    struct node {
        line l;
        int id;
        node *left=nullptr;
        node *right=nullptr;
        node(line _l=line(),int _id=-1):l(_l),left(nullptr),right(nullptr),id(_id){}
    };
    node neutral={line(),-1};
public:
    node *root=nullptr;
    ll  x_min,x_max;
    void init(ll  a,ll  b) {
        x_min=a,x_max=b;
    }
    void insert(line x,int id,ll  lx,ll  rx,node *&nd) {
        if (!nd) {
            nd=new  node(x,id);
            return;
        }
        ll m=(lx+rx)/2;
        bool m_b=x.evaluate(m)>nd->l.evaluate(m);
        bool l_b=x.evaluate(lx)>nd->l.evaluate(lx);
        if (m_b) {
            swap(x,nd->l);
            swap(id,nd->id);
        }
        if (rx-lx==0) {
            return;
        }
        if (l_b!=m_b) {
            insert(x,id,lx,m,nd->left);
        }
        else
            insert(x,id,m+1,rx,nd->right);
    }
    void insert(ll m,ll p,int id) {
        insert(line(m,p),id,x_min,x_max,root);
    }
    node  calc(ll x,ll lx,ll rx,node *nd) {
        if (!nd) {
            return node();
        }
        ll val=nd->l.evaluate(x);
        if (rx-lx==0) {
            return {nd->l,nd->id};
        }
        ll  m=(lx+rx)/2;
        if (x<=m) {
            node a=calc(x,lx,m,nd->left);
            if (val>a.l.evaluate(x)) {
                return {nd->l,nd->id};
            }
            else {
                return a;
            }
        }
        else {
            node b=calc(x,m+1,rx,nd->right);
            if (val>b.l.evaluate(x)) {
                return {nd->l,nd->id};
            }
            else {
                return b;
            }
        }
    }
    int   calc(ll x) {
        return calc(x,x_min,x_max,root).id;
    }
};
void solve() {
    int n,k;
    cin>>n>>k;
    k++;
    int a[n+1];
    for (int i=1;i<=n;i++) {
        cin>>a[i];
    }
    ll dp[n+1][k+1];
    int best[n+1][k+1];
    dp[0][0]=0LL;
    li_chao tree[k+1];
    for (int i=0;i<=k;i++) {
        tree[i].init(0,1e9);
    }
    ll pref[n+1];
    pref[0]=0LL;
    for (int i=1;i<=n;i++) {
        pref[i]=pref[i-1]+a[i];
    }
    for (int i=1;i<=n;i++) {
        for (int j=1;j<=k;j++) {
            if (j==1) {
                dp[i][1]=0;
                best[i][1]=0;
            }
            else {
                int g=tree[j-1].calc(pref[i]);
                best[i][j]=g;
                if (g!=-1) {
                    dp[i][j]=dp[g][j-1]+(pref[i]-pref[g])*pref[g];
                }
            }
        }
        for (int j=1;j<=k;j++) {
            if (best[i][j]!=-1) {
                tree[j].insert(pref[i],dp[i][j]-pref[i]*pref[i],i);
            }
        }
    }
    cout<<dp[n][k]<<endl;
    int cur=n;
    V<int>vp;
    for (int i=k;i>=2;i--) {
        vp.pb(best[cur][i]);
        cur=best[cur][i];
    }
    reverse(all(vp));
    for (auto u:vp) {
        cout<<u<<" ";
    }
    cout<<endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    //file();
    solve();
    return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'void file()':
sequence.cpp:14:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |     freopen("input.txt","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
sequence.cpp:15:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |     freopen("output.txt","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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