Cod sursa(job #1157056)

Utilizator cosmin.pascaruPascaru Cosmin cosmin.pascaru Data 28 martie 2014 11:09:44
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.28 kb
#include <fstream>

#define NMAX 100005
#define zeros(x) x & (-x)
using namespace std;

ifstream fin("aib.in");
ofstream fout("aib.out");

int n;
int aib[NMAX];

void add(int poz, int x)
{
    for (; poz <= n; poz += zeros(poz))
        aib[poz] += x;
}
int query(int poz)
{
    int rez = 0;
    for (; poz > 0; poz -= zeros(poz))
        rez += aib[poz];
    return rez;
}
int caut(int val)
{
    int step = 1;
    while (step < n) step <<= 1;

    int k;
    for (k = 0; step; step >>= 1)
        if (k+step <= n && aib[k+step] <= val)
        {
            k += step;
            val -= aib[k];
            if (!val) return k;
        }
    if (val != 0) return -1;
    //return k;
}
int main()
{
    int cod, a, b, x;
    int m;

    fin >> n >> m;
    for (int i = 1; i <= n; ++i)
    {
        fin >> x;
        add(i,x);
    }
    while (m--)
    {
        fin >> cod;
        if (cod == 0)
        {
            fin >> a >> b;
            add(a,b);
        }
        else if (cod == 1)
        {
            fin >> a >> b;
            fout << query(b) - query(a-1) << '\n';
        }
        else
        {
            fin >> a;
            fout << caut(a) << '\n';
        }
    }
    fin.close();
    fout.close();
    return 0;
}