Cod sursa(job #2750639)

Utilizator davidgogoanaGogoana David davidgogoana Data 12 mai 2021 17:29:21
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.27 kb
#include <fstream>
 
using namespace std;
 
ifstream fin("aib.in");
ofstream fout("aib.out");
 
const int NMAX=100000;
int aib[NMAX+5],n;
 
void update(int poz, int val)
{
    for( ;poz<=n;poz+=poz^(poz&(poz-1)))
        aib[poz]+=val;
}
 
int query(int poz)
{
    int sum=0;
    for( ;poz>=1;poz-=poz^(poz&(poz-1)))
        sum+=aib[poz];
    return sum;
}
 
int main()
{
    int m,i,a,b,op,k,dr,st,med,last;
    fin>>n>>m;
    for(i=1;i<=n;i++)
    {
        fin>>a;
        update(i,a);
    }
    for(i=1;i<=m;i++)
    {
        fin>>op>>a;
        if(op==0)
        {
            fin>>b;
            update(a,b);
        }
        else if(op==1)
        {
            fin>>b;
            fout<<query(b)-query(a-1)<<"\n";
        }
        else
        {
            st=1;
            dr=n;
            last=-1;
            while(st<=dr)
            {
                med=(st+dr)/2;
                k=query(med);
                if(k<a)
                    st=med+1;
                else
                {
                    last=med;
                    dr=med-1;
                }
            }
            if(last!=-1&&query(last)!=a)
                last=-1;
            fout<<last<<"\n";
        }
    }
    return 0;
}