Cod sursa(job #2729290)

Utilizator cdenisCovei Denis cdenis Data 24 martie 2021 15:50:53
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.2 kb
#include <iostream>
#include <fstream>

using namespace std;

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

int n,m,T[100005],k,a,b,val;

void add(int i, int k)
{
    while(i<=n)
    {
        T[i]+=k;
        i+=i&-i;
    }
}

int sum(int i)
{
    int sum=0;
    while(i>0)
    {
        sum+=T[i];
        i-=i&-i;
    }
    return sum;
}

int bin_src(int a)
{
    int st=1,dr=n;
    while(st<=dr)
    {
        int m=(st+dr)/2;
        int s=sum(m);
        if(s==a)
            return m;
        else if(a>s)
            st=m+1;
        else
            dr=m-1;
    }
    return 0;
}

int main()
{
    fin >> n >> m;
    for(int i=1;i<=n;i++)
    {
        fin >> k;
        add(i,k);
    }
    for(;m;--m)
    {
        fin >> val >> a;
        if(val==0)
        {
            fin >> b;
            add(a,b);
        }
        else if(val==1)
        {
            fin >> b;
            fout << sum(b)-sum(a-1) << '\n';
        }
        else if(val==2)
        {
            int ans=bin_src(a);
            if(ans)
                fout << ans << '\n';
            else
                fout << -1 << '\n';
        }
    }
	return 0;
}