Cod sursa(job #2424683)

Utilizator AndreiStrAndrei Stroici AndreiStr Data 23 mai 2019 17:46:59
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.94 kb
#include <bits/stdc++.h>

using namespace std;
ifstream f("aib.in");
ofstream g("aib.out");
int n,m,c,x,y,a[100001];
void aduna(int p,int y)
{
    for(;p<=n;p+=p&(-p))
        a[p]+=y;
}
int suma(int p)
{
    int s=0;
    for(;p;p-=p&(-p))
        s+=a[p];
    return s;
}
int cauta(int a)
{
    int lo=0,hi=n,mi;
    while(hi-lo>1)
    {
        mi=(lo+hi)/2;
        if(suma(mi)>=a)
            hi=mi;
        else
            lo=mi;
    }
    if(suma(hi)!=a)hi=-1;
    return hi;
}

int main()
{
    f>>n>>m;
    for(int i=1;i<=n;i++)
    {
        f>>x;
        aduna(i,x);
    }
    for(int i=1;i<=m;i++)
    {
        f>>c>>x;
        if(c==0)
        {
            f>>y;
            aduna(x,y);
        }
        else if(c==1)
        {
            f>>y;
            g<<suma(y)-suma(x-1)<<'\n';
        }
        else
        {
            g<<cauta(x)<<'\n';
        }
    }
    return 0;
}