Cod sursa(job #1995474)

Utilizator FredyLup Lucia Fredy Data 28 iunie 2017 01:06:57
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.32 kb
#include <iostream>
#include <fstream>

using namespace std;

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

#define lim 100010
int n,m,aib[lim];

void update(int pos, int val)
{
    for(; pos<=n; pos+=(pos&(-pos)))
        aib[pos]+=val;
}

int sum(int pos)
{
    int rez=0;
    for(; pos; pos-=(pos&(-pos)))
        rez+=aib[pos];
    return rez;
}


int query(int st, int dr)
{
    return sum(dr)-sum(st-1);
}


///pozitia minima k astfel incat suma valorilor primilor k termeni sa fie exact a
int b_s(int val)
{
    int mask,pos;
    for(mask=1; mask<=n; mask<<=1);
    for(pos=n; mask; mask>>=1)
        if(pos-mask>0)
            if(query(1,pos-mask)>=val)
                pos-=mask;
    if(query(1,pos)==val)
        return pos;
    return -1;
}


int main()
{
    int tip,x,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);
        }
        if(tip==1)
        {
            fin>>a>>b;
            fout<<query(a,b)<<'\n';
        }
        if(tip==2)
        {
            fin>>a;
            fout<<b_s(a)<<'\n';
        }
    }


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