Cod sursa(job #2198887)

Utilizator gavra_bogdanBogdan Gavra gavra_bogdan Data 25 aprilie 2018 19:03:02
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.09 kb
#include <bits/stdc++.h>
#define NMAX 100005
using namespace std;
int aib[NMAX],n;
void update(int poz,int x)
{
    for(int i=poz; i<=n; i+=(i&(-i)))
        aib[i]+=x;
}
int query(int poz)
{
    int sol=0;
    for(int i=poz; i>0; i-=(i&(-i)))
        sol+=aib[i];
    return sol;
}
int squery(int sum)
{
    int p=0,s=0;
    for(int i=20; i>=0; i--)
    {
        if(p+(1<<i)>n)
            continue;
            if(s+aib[(1<<i)+p]<sum)
        {
            p+=(1<<i);
            s+=aib[p];
        }
    }
    if(query(p+1)==sum)
        return p+1;
    else
        return -1;
}
int main()
{
    ifstream cin("aib.in");
    ofstream cout("aib.out");
    int m,c;
    cin>>n>>m;
    for(int i=1; i<=n; i++)
    {
        cin>>c;
        update(i,c);
    }
    int val,x,y;
    for(int i=1; i<=m; i++)
    {
        cin>>val>>x;
        if(val<2)
            cin>>y;
        if(val==0)
            update(x,y);
        if(val==1)
            cout<<query(y)-query(x-1)<<"\n";
        if(val==2)
            cout<<squery(x)<<"\n";
    }
    return 0;
}