Cod sursa(job #909284)

Utilizator TeodoraTanaseTeodora Tanase TeodoraTanase Data 10 martie 2013 15:06:35
Problema Arbori indexati binar Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.47 kb
#include <cstdio>
#include <algorithm>

#define NMAX 100001

using namespace std;

int n;
int aib[NMAX];

int zeros(int x)
{
    int k = 0;

    for(; ((1 << k) <= x) && (((1 << k) & x) == 0); ++ k);

    return k;
}

void add(int poz, int val)
{
    aib[poz] += val;

    int k = (1 << zeros(poz));

    if(poz + k <= n)
        add(poz + k, val);
}

void readArray()
{
    int x;

    for(int i = 1; i <= n; ++ i)
    {
        scanf("%d ", &x);
        add(i, x);
    }
}

int sum(int poz)
{
    int k = (1 << zeros(poz));

    if(poz - k > 0)
        return aib[poz] + sum(poz - k);

    return aib[poz];
}

int find_(int a)
{
    int st = 1;
    int dr = n;

    while(st <= dr)
    {
        int mij = (st + dr) >> 1;
        int aux = sum(mij);

        if(aux == a)
            return mij;

        if(aux < a)
            st = mij + 1;
        else
            dr = mij;
    }

    return -1;
}

int main()
{
    int m;
    int c;
    int a;
    int b;

    freopen("aib.out", "w", stdout);
    freopen("aib.in", "r", stdin);
    scanf("%d %d\n", &n, &m);

    readArray();

    while(m --)
    {
        scanf("%d %d ", &c, &a);

        if(c != 2)
        {
            scanf("%d ", &b);

            if(c == 0)
                add(a, b);
            else
                printf("%d\n", sum(b) - sum(a - 1));
        }
        else
            printf("%d\n", find_(a));
    }

    return 0;
}