Cod sursa(job #2375625)

Utilizator dacianouaPapadia Mortala dacianoua Data 8 martie 2019 11:06:25
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.19 kb
#include <iostream>
#include <fstream>
#define nmax 100000
using namespace std;
ifstream fin("aib.in");
ofstream fout("aib.out");
int n,m,aib[nmax+5];
void update(int poz,int val)
{
    while(poz<=n)
    {
        aib[poz]+=val;
        poz+=poz&(-poz);
    }
}
int sum(int poz)
{
    int s=0;
    while(poz>0)
    {
        s+=aib[poz];
        poz-=poz&(-poz);
    }
    return s;
}
int kth(int s)
{
    int p=1;
    while(p<n)p<<=1;
    for(int i=0;p>0;p>>=1)
        if(i+p<=n)
        {
            if(s>=aib[i+p])
            {
                i+=p;
                s-=aib[i];
                if(!s)
                    return i;
            }
        }
    return -1;
}
int main()
{
    fin>>n>>m;
    int x,y,z;
    for(int i=1;i<=n;i++)
        fin>>x,update(i,x);
    for(int i=1;i<=m;i++)
    {
        fin>>z;
        switch(z)
        {
        case 0:
            fin>>x>>y;
            update(x,y);
            break;
        case 1:
            fin>>x>>y;
            fout<<sum(y)-sum(x-1)<<"\n";
            break;
        case 2:
            fin>>x;
            fout<<kth(x)<<"\n";
            break;
        }
    }
    return 0;
}