Cod sursa(job #2868206)

Utilizator 21CalaDarius Calaianu 21Cala Data 10 martie 2022 19:44:04
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.29 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <stack>
#define NMAX 100005
using namespace std;
ifstream fin ("aib.in");
ofstream fout ("aib.out");
int n,m;
long s[NMAX];
void update(long poz, long val)
{
    for(int i=poz;i<=n;i+=(i & -i))
    {
        s[i]+=val;
    }
}
int query(long poz)
{
    int sum=0;
    for(int i=poz;i>0;i-=(i & -i))
    {
        sum+=s[i];
    }
    return sum;
}
int findk(long sum)
{
    int l=1,r=n,m;
    while(l<=r)
    {
        m=(l+r)/2;
        if(query(m)>=sum)
        {
            r = m-1;
        }
        else
        {
            l = m+1;
        }
    }
    if(query(l)==sum)
            return l;
    return -1;
}
void read()
{
    int nr;
    fin >> n >> m;
    for(int i=1;i<=n;++i)
    {
        fin >> nr;
        update(i,nr);
    }
}
int main()
{
    read();
    int t,a,b;
    for(int i=0;i<m;++i)
    {
        fin >> t;
        if(t==0)
        {
            fin >> a >> b;
            update(a,b);
        }
        else if(t==1)
        {
            fin >> a >> b;
            fout << query(b)-query(a-1) << '\n';
        }
        else
        {
            fin >> a;
            fout << findk(a) << '\n';
        }
    }
    return 0;
}