Cod sursa(job #1506984)

Utilizator AndreiIstetulAndrei Andrei AndreiIstetul Data 21 octombrie 2015 10:07:54
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.54 kb
#include <iostream>
#include <fstream>
#include <cstdio>

using namespace std;

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

int n,m,aib[100001];

inline int zeros(int x)
{
    return (-x)&x;
}

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

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

int Search(int val)
{
    int i, step;

    for ( step = 1; step < n; step <<= 1 );

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

    return -1;
}

int main()
{
    freopen("aib.in","r",stdin);
    freopen("aib.out","w",stdout);
    scanf("%d%d",&n, &m); int x;
    for (int i=1; i<=n; ++i)
    {
        scanf("%d",&x);
        update(i,x);
    }
    for (int i=1; i<=m; ++i)
    {
        int caz; scanf("%d",&caz);
        int a,b;
        switch(caz)
        {
            case 0:
                    scanf("%d%d",&a,&b);
                    update(a,b);
                    break;
            case 1:
                    scanf("%d%d",&a,&b);
                    printf("%d\n",sum(b)-sum(a-1));
                    break;
            case 2:
                    scanf("%d",&a);
                    printf("%d\n",Search(a));
                    break;
        }
    }
    return 0;
}