Cod sursa(job #3159423)

Utilizator Robert_MitriRobert Mitri Robert_Mitri Data 21 octombrie 2023 12:00:38
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.25 kb
#include <fstream>
using namespace std;
ifstream fin("aib.in");
ofstream fout("aib.out");

int n,q;

int aib[100005];

void update(int poz,int nr)
{
    for(int i = poz ; i <= n;i += (i&(-i)))
        aib[i] += nr;
}
int query(int poz)
{
    int s = 0 ;
    for(int i = poz ; i>0 ; i-= (i&(-i)))
        s+= aib[i];
    return s;
}

int cb(int val)
{
    int st = 1;
    int dr = n;
    int pp = -1;
    while(st<=dr)
    {
        int mid = (st+dr)/2;
        int nr = query(mid);
        if(nr>=val)
        {
            dr=mid-1;
            if(nr==val)
                pp=mid;
        }
        else
            st=mid+1;
    }
    return pp;
}

int main()
{
    fin>>n>>q;
    for(int i = 1; i<=n;i++)
        {
            int x;
            fin>>x;
            update(i,x);
        }
    for(int i = 1;i<=q;i++)
    {
        int t;
        fin>>t;
        if(t==0)
        {
            int a,b;
            fin>>a>>b;
            update(a,b);
        }
        else if (t==1)
        {
            int a,b;
            fin>>a>>b;
            fout<<query(b)-query(a-1)<<'\n';
        }
        else
        {
            int x;
            fin>>x;
            fout<<cb(x)<<'\n';
        }
    }

}