Cod sursa(job #2182717)

Utilizator AlexutAlex Calinescu Alexut Data 22 martie 2018 16:41:20
Problema Arbori indexati binar Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 1.34 kb
#include <fstream>

using namespace std;
long long aib[100005];
int n;
void update(int poz,int val)
{
    for(;poz<=n;poz+=(poz&-poz))
        aib[poz]+=val;
}
long long query(int poz)
{
    long long s=0;
    for(;poz>0;poz-=(poz&-poz))
        s+=aib[poz];
    return s;
}
long long sp[100005];
int main()
{
    ifstream cin ("aib.in");
    ofstream cout ("aib.out");

    int x,p,i,j;
    cin>>n;
    cin>>p;
    for(i=1;i<=n;i++)
    {
       cin>>x;
       sp[i]=sp[i-1]+x;
    }
    for(i=1;i<=n;i++)
    {
        aib[i]=sp[i]-sp[i-(i&-i)];
    }
    int y,z;
    for(i=1;i<=p;i++)
    {
        cin>>x>>y;
        if(x==0)
        {
            cin>>z;
            update(y,z);
        }
        else if(x==1)
        {
            cin>>z;
            cout<<query(z)-query(y-1)<<endl;
        }
        else
        {
         int st=1,dr=n,ok=0;
          while(st<=dr)
          {
            int med=(st+dr)>>1;
            int suma=query(med);
            if(suma==y)
            {
                cout<<med<<endl;
                ok=1;
                break;
            }
            if(suma>y)dr=med-1;
            else
                st=med+1;
          }
          if(ok==0)
          {
            cout<<-1<<endl;
            continue;
          }

        }
    }
    return 0;
}