Cod sursa(job #329497)

Utilizator DraStiKDragos Oprica DraStiK Data 6 iulie 2009 12:58:59
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.36 kb
#include <stdio.h>
#define DIM 100005

int aib[DIM];
int n,m;

int lsb (int x)
{
    return x&(x-1)^x;
}

void update (int poz,int val)
{
    for ( ; poz<=n; poz+=lsb (poz))
        aib[poz]+=val;
}

void read ()
{
    int i,x;
    scanf ("%d%d",&n,&m);
    for (i=1; i<=n; ++i)
    {
        scanf ("%d",&x);
        update (i,x);
    }
}

int query (int poz)
{
    int sum;
    for (sum=0; poz; poz-=lsb (poz))
        sum+=aib[poz];
    return sum;
}

int cbin (int val)
{
    int st,dr,mij,nr;
    for (st=1, dr=n; st<=dr; )
    {
        mij=(st+dr)/2;
        nr=query (mij);
        if (nr==val)
            return mij;
        else if (nr<val)
            st=mij+1;
        else
            dr=mij-1;
    }
    return -1;
}

void solve ()
{
    int i,cod,x,y;
    for (i=1; i<=m; ++i)
    {
        scanf ("%d",&cod);
        if (cod==0)
        {
            scanf ("%d%d",&x,&y);
            update (x,y);
        }
        else if (cod==1)
        {
            scanf ("%d%d",&x,&y);
            printf ("%d\n",query (y)-query (x-1));
        }
        else if (cod==2)
        {
            scanf ("%d",&x);
            printf ("%d\n",cbin (x));
        }
    }
}

int main ()
{
    freopen ("aib.in","r",stdin);
    freopen ("aib.out","w",stdout);
    read ();
    solve ();
    return 0;
}