Cod sursa(job #3250497)

Utilizator Dragu_AndiDragu Andrei Dragu_Andi Data 21 octombrie 2024 15:26:39
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.5 kb
#include <iostream>
#include <fstream>

using namespace std;

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

const int nmax=1e5 +1;
int aint[nmax*4], v[nmax];

void build_aint(int nod, int st, int dr)
{
    if(st==dr)
    {
        aint[nod]=v[st];
        return;
    }
    build_aint(nod*2, st, (st+dr)/2);
    build_aint(nod*2+1, (st+dr)/2+1, dr);
    aint[nod]=max(aint[nod*2], aint[nod*2+1]);
}

void update(int pos, int val, int nod, int st, int dr)
{
    if(st==dr)
    {
        aint[nod]=val;
        return;
    }
    if(pos<=(st+dr)/2)
        update(pos, val, nod*2, st, (st+dr)/2);
    else
        update(pos, val, nod*2+1, (st+dr)/2+1, dr);
    aint[nod]=max(aint[nod*2], aint[nod*2+1]);
}

int ans;

void query(int a, int b, int nod, int st, int dr)
{
    if(a<=st && b>=dr)
    {
        ans=max(ans, aint[nod]);
        return;
    }
    if(a<=(st+dr)/2)
        query(a, b, 2*nod, st, (st+dr)/2);
    if(b>(st+dr)/2)
        query(a, b, 2*nod+1, (st+dr)/2+1, dr);
}

void query_start(int a, int b, int n)
{
    ans=0;
    query(a, b, 1, 1, n);
    fout << ans << '\n';
}

int main()
{
    int n, m;
    fin >> n >> m;
    for(int i=1; i<=n; i++)
        fin >> v[i];
    build_aint(1, 1, n);
    int c, a, b;
    for(int i=1; i<=m; i++)
    {
        fin >> c >> a >> b;
        if(c)
        {
            update(a, b, 1, 1, n);
        }
        else
        {
            query_start(a, b, n);
        }
    }
    return 0;
}