Cod sursa(job #2070701)

Utilizator anisca22Ana Baltaretu anisca22 Data 19 noiembrie 2017 20:34:04
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.33 kb
#include <bits/stdc++.h>
#define NMAX 100005

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

int N, M;
int aib[NMAX];

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

int query(int poz)
{
    int Sum = 0;
    while (poz > 0)
    {
        Sum += aib[poz];
        poz -= (poz & -poz);
    }
    return Sum;
}

int cauta(int val)
{
    int step;
    for (step = 1; step < N; step <<= 1);

    for (int i = 0; step; step >>= 1)
    {
        if (i + step <= N && val >= aib[i + step])
        {
            i += step;
            val -= aib[i];
            if (val == 0)
                return i;
        }
    }
    return -1;
}

int main()
{
    fin >> N >> M;
    for (int i = 1; i <= N; i++)
    {
        int a;
        fin >> a;
        update(i, a);
    }
    for (int i = 1; i <= M; i++)
    {
        int op, a, b;
        fin >> op;
        if (op == 0)
        {
            fin >> a >> b;
            update(a, b);
        }
        else if (op == 1)
        {
            fin >> a >> b;
            fout << query(b) - query(a - 1) << "\n";
        }
        else if (op == 2)
        {
            fin >> a;
            fout << cauta(a) << "\n";
        }
    }
    return 0;
}