Cod sursa(job #2113527)

Utilizator alextodoranTodoran Alexandru Raul alextodoran Data 24 ianuarie 2018 18:38:20
Problema Arbori indexati binar Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.37 kb
#include <iostream>
#include <fstream>
using namespace std;

int n, v[100002], k, bbn;

int bb (int n)
{
    int i;
    for(i = 0; (1 << i) <= n; i++);
    return i - 1;
}

int lsb (int n)
{
    return n & (n - 1) ^ n;
}

void update (int p, int val)
{
    for(int j = p; j <= n; j += lsb(j))
    {
        v[j] += val;
    }
}

int query (int p)
{
    int s = 0;
    for(int j = p; j > 0; j -= lsb(j))
    {
        s += v[j];
    }
    return s;
}

int query2 (int val)
{
    int rez = 0, p = 0;
    for(int i = bbn; val > 0; i--)
    {
        if(v[p + (1 << i)] <= val)
        {
            rez += (1 << i);
            p += (1 << i);
            val -= v[p];
        }
    }
    return rez;
}

int main()
{
    ifstream fin ("aib.in");
    ofstream fout ("aib.out");
    fin >> n >> k;
    bbn = bb(n);
    for(int i = 1; i <= n; i++)
    {
        int e;
        fin >> e;
        update(i, e);
    }
    for(int i = 1; i <= k; i++)
    {
        int o, a, b;
        fin >> o;
        if(o == 0)
        {
            fin >> a >> b;
            update(a, b);
        }
        else if(o == 1)
        {
            fin >> a >> b;
            fout << query(b) - query(a - 1) << "\n";
        }
        else
        {
            fin >> a;
            fout << query2(a) << "\n";
        }
    }
    return 0;
}