Cod sursa(job #2750650)

Utilizator Horis21Horia Radu Horis21 Data 12 mai 2021 17:49:04
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.07 kb
#include <iostream>
#include <fstream>

using namespace std;

ifstream in ("arbint.in");
ofstream out ("arbint.out");

const int N= 1<<18;

int t[N],a,b,pos,val;

int ask(int p, int l, int r)
{
    if(a<=l && r<=b)
    {
        return t[p];
    }
    int h=(l+r)/2,maxl,maxr;
    if(a<=h) maxl=ask(2*p,l,h);
    else maxl=-1;
    if(h<b) maxr=ask(2*p+1,h+1,r);
    else maxr=-1;
    return max(maxl,maxr);
}

void update(int p, int l, int r)
{
    if(l>=r)
    {
        t[p]=val;
        return;
    }
    int h=(l+r)/2;
    if(pos<=h) update(2*p,l,h);
    else update(2*p+1,h+1,r);
    t[p]=max(t[2*p],t[2*p+1]);
}

int main()
{
    int n,m;
    in >> n >> m;
    for(int i=0;i<n;i++)
    {
        in >> val;
        pos=i+1;
        update(1,1,n);
    }
    for(int i=0;i<m;i++)
    {
        int q;
        in >> q;
        if(!q)
        {
            in >> a >> b;
            out << ask(1,1,n) << "\n";
        }
        else
        {
            in >> pos >> val;
            update(1,1,n);
        }
    }
    return 0;
}