Cod sursa(job #2884002)

Utilizator anastasei_tudorAnastasei Tudor anastasei_tudor Data 2 aprilie 2022 10:22:45
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.32 kb
#include <bits/stdc++.h>
#define lsb(x) ((x^(x-1))+1)/2
#define NMAX 100004

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

int n, m;
int aib[NMAX];

void update(int poz, int val);
int sum(int poz);
int caut_binar(int x);

int main()
{
    int x, tip, a, b;
    fin >> n >> m;
    for (int i = 1; i <= n; i++)
    {
        fin >> x;
        update(i, x);
    }

    for (int i = 1; i <= m; i++)
    {
        fin >> tip;
        if (tip == 0)
        {
            fin >> a >> b;
            update(a, b);
        }
        else if (tip == 1)
        {
            fin >> a >> b;
            fout << sum(b) - sum(a-1) << '\n';
        }
        else
        {
            fin >> a;
            fout << caut_binar(a) << '\n';
        }
    }
    return 0;
}

void update(int poz, int val)
{
    for (int i = poz; i <= n; i += lsb(i))
        aib[i] += val;
}

int sum(int poz)
{
    int s = 0;
    for (int i = poz; i; i -= lsb(i))
        s += aib[i];
    return s;
}

int caut_binar(int x)
{
    int st = 0, dr = n + 1, mij;
    while (dr - st > 1)
    {
        mij = (st + dr) / 2;
        if (sum(mij) < x)
            st = mij;
        else if (sum(mij) > x)
            dr = mij;
        else
            return mij;
    }
    return -1;
}