Cod sursa(job #1553371)

Utilizator andreiudilaUdila Andrei andreiudila Data 19 decembrie 2015 18:26:59
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.19 kb
#include <fstream>
using namespace std;
ifstream fin("aib.in");
ofstream fout("aib.out");

int n,m,i,op,x,y;
int aib[100001];

void update(int a, int b)
{
    while(a<=n)
    {
        aib[a]+=b;
        a=a+(a&(-a));
    }

}

int query(int a, int b)
{
    int suma=0;
    while(b>0)
    {
    suma+=aib[b];
    b=b-(b&(-b));
    }

    --a;

    while(a>0)
    {
      suma-=aib[a];
      a=a-(a&(-a));
    }

    return suma;

}

int poz(int a)
{
    int l=1;
    int r=n;

    while(l<=r)
    {
        int mid=(l+r)/2;

        int q=query(1,mid);

        if(q>a) r=mid-1;
        else if (q<a) l=mid+1;
        else return mid;
    }

   return -1;
}

int main()
{

    fin>>n>>m;

    for(i=1;i<=n;i++)
        {
            fin>>x;
            update(i,x);
        }


    for(i=1;i<=m;i++)
    {
        fin>>op;

        if(op==0)
        {
            fin>>x>>y;
            update(x,y);
        }
        else if(op==1)
        {
            fin>>x>>y;
            fout<<query(x,y)<<'\n';
        }

        else
        {
            fin>>x;
            fout<<poz(x)<<'\n';
        }

    }
    return 0;
}