Submission #868988

#	Time	Username	Problem	Language	Result	Execution time	Memory
868988		alexdd	Bigger segments (IZhO19_segments)	C++17	37 / 100	214 ms	262144 KiB

segments

#include<bits/stdc++.h>
using namespace std;
const long long INF = 1e18;
int n;
int a[500005];
int dp[500005];
long long ult[500005];
long long pref[500005];
struct node
{
    int dpval=-1;
    int ultval=-1;
    int tole=-1;
    int tori=-1;
};
node mymax(node x, node y)
{
    node rez;
    if(x.dpval>y.dpval)
        return x;
    if(x.dpval<y.dpval)
        return y;
    if(x.ultval>y.ultval)
        return x;
    return y;
}
node emp;
vector<node> aint;
void upd(int nod, long long st, long long dr, long long poz, node newv)
{
    if(st==dr)
    {
        aint[nod]=mymax(aint[nod],newv);
        return;
    }
    if(aint[nod].tole==-1)
    {
        aint[nod].tole=aint.size();
        aint.push_back(emp);
    }
    if(aint[nod].tori==-1)
    {
        aint[nod].tori=aint.size();
        aint.push_back(emp);
    }
    long long mij=(st+dr)/2;
    if(poz<=mij) upd(aint[nod].tole,st,mij,poz,newv);
    else upd(aint[nod].tori,mij+1,dr,poz,newv);

    node aux = mymax(aint[aint[nod].tole], aint[aint[nod].tori]);
    aint[nod].dpval = aux.dpval;
    aint[nod].ultval = aux.ultval;
}
node qry(int nod, long long st, long long dr, long long le, long long ri)
{
    if(le>ri)
        return emp;
    if(le==st && dr==ri)
        return aint[nod];
    if(aint[nod].tole==-1)
    {
        aint[nod].tole=aint.size();
        aint.push_back(emp);
    }
    if(aint[nod].tori==-1)
    {
        aint[nod].tori=aint.size();
        aint.push_back(emp);
    }
    long long mij=(st+dr)/2;
    return mymax(qry(aint[nod].tole,st,mij,le,min(mij,ri)),
                 qry(aint[nod].tori,mij+1,dr,max(mij+1,le),ri));
}
signed main()
{
    emp={-1,-1,-1,-1};
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
        pref[i]=pref[i-1]+a[i];
    }
    dp[0]=0;
    ult[0]=0;
    aint.push_back(emp);
    upd(0,0,INF,0,{0,0,-1,-1});
    for(int i=1;i<=n;i++)
    {
        node aux = qry(0,0,INF,0,pref[i]);
        dp[i]=aux.dpval+1;
        ult[i]=pref[i]-pref[aux.ultval];
        if(dp[i-1]>dp[i] || (dp[i-1]==dp[i] && ult[i-1]+a[i]<ult[i]))
        {
            dp[i]=dp[i-1];
            ult[i]=ult[i-1]+a[i];
        }
        upd(0,0,INF,ult[i]+pref[i],{dp[i],i,-1,-1});
    }
    cout<<dp[n];
    return 0;
}
/**

dp[i] = numarul maxime de secvente in care pot fi impartite primele i elemente
ult[i] = suma ultimei secvente din solutia pt dp[i]
dp[i] max= dp[i-1]
dp[i] max= max(dp[x]+1) pt x = 0..i-1 && ult[x] + pref[x] <= pref[i]


*/

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 0 / 36
• Subtask 5: 0 / 27