Cod sursa(job #3297969)

Utilizator Cristian_NegoitaCristian Negoita Cristian_Negoita Data 25 mai 2025 10:26:56
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.3 kb
#include <bits/stdc++.h>
using namespace std;
ifstream fin("aib.in");
ofstream fout("aib.out");
#define lsb(i) (i & (-i))
const int NMAX = 100001;
int n, q, a[NMAX], aib[NMAX];

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

int query(int poz)
{
    int ans = 0;
    for(int i = poz; i >= 1; i -= lsb(i))
        ans += aib[i];
    return ans;
}

int caut_bin(int val)
{
    int st = 1, dr = n;
    while(st <= dr)
    {
        int mid = (st + dr) / 2;
        if(query(mid) == val)
            return mid;
        else if(query(mid) < val)
            st = mid + 1;
        else
            dr = mid - 1;
    }
    return -1;
}

int main()
{
    fin >> n >> q;
    for(int i = 1; i <= n; i++)
    {
        int val;
        fin >> val;
        update(i, val);
    }
    while(q--)
    {
        int tip, a, b;
        fin >> tip;
        if(tip == 0)
        {
            fin >> a >> b;
            update(a, b);
        }
        else if(tip == 1)
        {
            fin >> a >> b;
            fout << query(b) - query(a - 1) << "\n";
        }
        else
        {
            fin >> a;
            fout << caut_bin(a) << "\n";
        }
    }

    fin.close();
    fout.close();
    return 0;
}