Cod sursa(job #526036)

Utilizator DraStiKDragos Oprica DraStiK Data 27 ianuarie 2011 09:28:32
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.38 kb
#include <algorithm>
using namespace std;

#define DIM 100005

int aib[DIM];
int n,m;

inline int lsb (int x)
{
    return x&-x;
}

inline 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);
    }
}

inline int query (int poz)
{
    int sum;

    for (sum=0; poz; poz-=lsb (poz))
        sum+=aib[poz];

    return sum;
}

inline int search (int val)
{
    int i,step;

    for (step=1; step<n; step<<=1);

    for (i=0; step; step>>=1)
        if (i+step<=n && val>=aib[i+step])
        {
            i+=step;
            val-=aib[i];
            if (val==0)
                return i;
        }
    return -1;
}

void solve ()
{
    int i,tip,x,y;

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

int main ()
{
    freopen ("aib.in","r",stdin);
    freopen ("aib.out","w",stdout);

    read ();
    solve ();

    return 0;
}