Cod sursa(job #2436568)

Utilizator hhhhhhhAndrei Boaca hhhhhhh Data 6 iulie 2019 12:37:08
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.41 kb
#include <bits/stdc++.h>

using namespace std;
ifstream fin("aib.in");
ofstream fout("aib.out");
int n,m,a,b,tip;
int v[100001];
int aib[100001];
int lsb(int x)
{
    return x&(-x);
}
void update(int pos,int val)
{
    v[pos]+=val;
    for(int q=pos;q<=n;q+=lsb(q))
        aib[q]+=val;
}
int sum(int pos)
{
    int rez=0;
    for(int q=pos;q>=1;q-=lsb(q))
        rez+=aib[q];
    return rez;
}
int main()
{
    fin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        fin>>v[i];
        update(i,v[i]);
    }
    for(int i=1;i<=m;i++)
    {
        fin>>tip;
        if(tip==0)
        {
            fin>>a>>b;
            update(a,b);
        }
        if(tip==1)
        {
            fin>>a>>b;
            fout<<sum(b)-sum(a-1)<<'\n';
        }
        if(tip==2)
        {
            fin>>a;
            int st=1;
            int dr=n;
            int mij;
            bool gasit=0;
            while(st<=dr)
            {
                mij=(st+dr)/2;
                if(sum(mij)==a)
                {
                    fout<<mij<<'\n';
                    gasit=1;
                    break;
                }
                else if(sum(mij)>a)
                {
                    dr=mij-1;
                }
                else
                    st=mij+1;
            }
            if(gasit==0)
                fout<<-1<<'\n';
        }
    }
    return 0;
}