Cod sursa(job #2090821)

Utilizator Andrei2000Andrei Mihailescu Andrei2000 Data 18 decembrie 2017 19:23:08
Problema Arbori indexati binar Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.1 kb
#include <bits/stdc++.h>

using namespace std;

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

const int nmax=100012;

int n,m,aib[nmax];

int lsb(int q){
    return q & -q;
}

void update(int q, int qq){
    while(q<=n){
        aib[q]+=qq;
        q+=lsb(q);
    }
}

int query(int q){
    int sum=0;
    while(q){
        sum+=1;
        q-=lsb(q);
    }
    return sum;
}

int searchaib(int q){
    int pos=0,c;
    for(c=1;c<=n;c<<=1);
    for(;c;c>>=1){
        if(pos+c<=n & aib[pos+c]<=q){
            pos+=c;
            q-=aib[pos];
            if(!q)return pos;
        }
    }
    return -1;
}

int main()
{
    int a,b,c;
    fin>>n>>m;
    for(int i=1;i<=n;++i){
        fin>>a;
        update(i,a);
    }
    for(int i=1;i<=m;++i){
        fin>>a;
        if(a<=1){
            fin>>b>>c;
            if(!a)
                update(b,c);
            else{
                fout<<query(c)-query(b-1)<<'\n';
            }
        }
        else{
            fin>>b;
            fout<<searchaib(b)<<'\n';
        }
    }
    return 0;
}