Cod sursa(job #1104494)

Utilizator traian2traian traian2 Data 10 februarie 2014 20:23:54
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.44 kb
#include<cstdio>
using namespace std;

#define Nmax 100005
int aib[Nmax],n,m,x;
void update(int poz, int val)
{
    while(poz<=n)
    {
        int k=poz & (-poz);
        aib[poz]+=val;
        poz= poz+ k;
    }
}
int query(int poz)
{
    int s=0;
    while(poz>0)
    {
        s+=aib[poz];
        int k=poz & (-poz);
        poz= poz - k;
    }
    return s;
}
int Search(int val)
{
    int i, step;

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

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

    return -1;
}
int main()
{
    freopen("aib.in","r",stdin);
    freopen("aib.out","w",stdout);
    scanf("%d%d",&n,&m);
    int i;
    for(i=1; i<=n; i++)
        {
            scanf("%d",&x);
            update(i,x);
        }
    int op, a,b;
    for(i = 1; i <= m; i++)
    {
        scanf("%d",&op);
        switch(op)
        {
            case 0: scanf("%d%d",&a,&b);
                    update(a,b);
                    break;
            case 1:scanf("%d%d",&a,&b);
                    printf("%d\n",query(b)-query(a-1));
                    break;
            case 2: scanf("%d",&a);
                    printf("%d\n",Search(a));
                    break;
        }
    }
    return 0;
}