Cod sursa(job #3288751)

Utilizator bogdan1479Luca Bogdan Alexandru bogdan1479 Data 24 martie 2025 09:44:37
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.24 kb
#include <fstream>

using namespace std;

const int NMAX = 1e5 + 1;

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

int n, aib[NMAX];

void add(int poz, int val)
{
    while(poz <= n)
    {
        aib[poz] += val;
        poz += poz & (-poz);
    }
}

int sum(int poz)
{
    int s = 0;
    while(poz)
    {
        s += aib[poz];
        poz &= (poz - 1);
    }
    return s;
}

int cb(int val)
{
    int i, step;
    for(step = 1; step < n; step <<= 1);
    for(i = 0; step; step >>= 1)
    {
        int poz = i + step;
        if(poz <= n && aib[poz] <= val)
        {
            val -= aib[poz];
            i = poz;
            if(!val) return i;
        }
    }
    return -1;
}

int main()
{
    int m, op, x, y;
    fin >> n >> m;
    for(int i = 1; i <= n; ++i)
    {
        fin >> x;
        add(i, x);
    }
    while(m--)
    {
        fin >> op;
        switch(op)
        {
        case 0:
            fin >> x >> y;
            add(x, y);
            break;
        case 1:
            fin >> x >> y;
            fout << sum(y) - sum(x - 1) << '\n';
            break;
        case 2:
            fin >> x;
            fout << cb(x) << '\n';
        }
    }
    return 0;
}