Cod sursa(job #1640305)

Utilizator george_stelianChichirim George george_stelian Data 8 martie 2016 16:56:27
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.18 kb
#include <cstdio>

using namespace std;

int aib[100010],n,logn;

void aib_update(int i,int s)
{
    for(;i<=n;i+=i&(-i)) aib[i]+=s;
}

int aib_query(int i)
{
    int s=0;
    for(;i>0;i-=i&(-i)) s+=aib[i];
    return s;
}

int cauta_binar(int s)
{
    int poz=0;
    for(int i=logn;i>=0;i--)
        if(poz+(1<<i)<=n && aib[poz+(1<<i)]<=s)
        {
            poz+=1<<i;
            s-=aib[poz];
            if(s==0) return poz;
        }
    return -1;
}

int main()
{
    freopen("aib.in", "r", stdin);
    freopen("aib.out", "w", stdout);
    int m,s,tip,a,b;
    scanf("%d%d",&n,&m);
    for(logn=1;(1<<logn)<=n;logn++);logn--;
    for(int i=1;i<=n;i++)
    {
        scanf("%d",&a);
        aib_update(i,a);
    }
    for(int i=1;i<=m;i++)
    {
        scanf("%d",&tip);
        if(tip==0)
        {
            scanf("%d%d",&a,&b);
            aib_update(a,b);
        }
        else if(tip==1)
        {
            scanf("%d%d",&a,&b);
            printf("%d\n",aib_query(b)-aib_query(a-1));
        }
        else
        {
            scanf("%d",&a);
            printf("%d\n",cauta_binar(a));
        }
    }
    return 0;
}