Cod sursa(job #2042217)

Utilizator LeVladzCiuperceanu Vlad LeVladz Data 18 octombrie 2017 10:42:44
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.2 kb
#include <fstream>

using namespace std;

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

int n,i,x,A[100001],m,op,a,b;

int query(int p)
{
    int r = 0;
    for (; p; p-=(p&-p))
        r += A[p];
    return r;
}

void update(int p, int x)
{
    for (; p<=n; p+=(p&-p))
        A[p] += x;
}

int main()
{
    fin >> n >> m;
    for (i=1; i<=n; i++)
    {
        fin >> x;
        update(i, x);
    }
    for (i=1; i<=m; i++)
    {
        fin >> op;
        if (op == 0)
        {
            fin >> a >> b;
            update(a, b);
        }
        if (op == 1)
        {
            fin >> a >> b;
            fout << query(b)-query(a-1) << "\n";
        }
        if (op == 2)
        {
            fin >> a;
            int st = 1;
            int dr = n;
            while (st <= dr)
            {
                int mid = (st+dr)/2;
                int rez = query(mid);
                if (rez < a)
                    st = mid+1;
                else
                    dr = mid-1;
            }
            if (query(st) == a)
                fout << st << "\n";
            else
                fout << -1 << "\n";
        }
    }
    return 0;
}