Cod sursa(job #954159)

Utilizator Al3ks1002Alex Cociorva Al3ks1002 Data 28 mai 2013 14:34:57
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.09 kb
#include<cstdio>
using namespace std;
int n,m,i,poz,val,a,b,arb[(1<<17)+5],op;
void add(int poz,int val)
{
    for(int i=poz;i<=n;i+=i&(-i)) arb[i]+=val;
}
int sum(int x)
{
    int s=0,i;
    for(i=x;i;i-=i&(-i)) s+=arb[i];
    return s;
}
int query(int x)
{
    int sol=0,step;
    for(step=1;step<=n;step<<=1);
    for(;step;step>>=1)
        if(sol+step<=n && arb[sol+step]<=x)
        {
            sol+=step; x-=arb[sol];
            if(!x) return sol;
        }
    return -1;
}
int main()
{
    freopen("aib.in","r",stdin);
    freopen("aib.out","w",stdout);
    scanf("%d%d",&n,&m);
    for(i=1;i<=n;i++)
    {
        scanf("%d",&val);
        add(i,val);
    }
    for(;m;m--)
    {
        scanf("%d",&op);
        if(op==0)
        {
            scanf("%d%d",&poz,&val);
            add(poz,val);
            continue;
        }
        if(op==1)
        {
            scanf("%d%d",&a,&b);
            printf("%d\n",sum(b)-sum(a-1));
            continue;
        }
        scanf("%d",&a);
        printf("%d\n",query(a));
    }
    return 0;
}