Cod sursa(job #1959501)

Utilizator ana-maria.simiAna-Maria Simionescu ana-maria.simi Data 9 aprilie 2017 16:11:52
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.77 kb
#include <fstream>
using namespace std;
int n,m,t,arb[100001],c,s,k,x,y;

void update(int,int);
int query(int);
int Search(int);

int main()
{
    freopen("aib.in","r",stdin);
    freopen("aib.out","w",stdout);
    scanf("%d%d", &n, &m);
    for(int i=1; i<=n; i++)
    {
        scanf("%d", &t);
        update(i,t);
    }

    for(int i=1; i<=m; i++)
    {
        scanf("%d", &k);
        if(k<2)
        {
             scanf("%d%d", &x, &y);
             if(!k)
                update(x,y);
                else
                    printf("%d\n", query(y)-query(x-1));
        }
        else
        {
            scanf("%d", &x);
            printf("%d\n", Search(x));
        }
    }
}

int Search(int sum)
{
    int poz=n+1,b=n,st=0,dr=n+1;
    s=query(b);
    if(s==sum)
        poz=n;
    while(b)
    {
          b=(st+dr)/2;
          s=query(b);
          if(s>sum)
          {
               if(dr>b)
                dr=b;
            b--;
          }
          else
            if(s==sum)
                {poz=min(poz,b);
                dr=b;
                b--;}
          else
          {
              if(st<b)
                st=b;
            b++;
          }
          if(b<=st)
            break;
          if(b>=dr)
           break;
    }
    if(poz==n+1)
        return -1;
    return poz;
}

void update(int poz, int val)
{
     c=0;
     while(poz<=n)
     {
           arb[poz]+=val;
           while(!(poz & (1<<c)))
                c++;
           poz+=(1<<c);
           c++;
     }
}

int query(int poz)
{
    c=0, s=0;
    while(poz>0)
    {
          s+=arb[poz];
          while(!(poz & (1<<c)))
                c++;
          poz-=(1<<c);
          c++;
    }

    return s;
}