Cod sursa(job #2986389)

Utilizator PingStrpewpewpac PingStr Data 28 februarie 2023 15:21:06
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.54 kb
#include <bits/stdc++.h>

using namespace std;

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

const int NMAX = 100002;
int n, m, x, c, v[NMAX], arb[4*NMAX];

int query(int nod, int st, int dr, int l, int r);
void build(int nod, int st, int dr);
void update(int nod, int st, int dr, int poz, int k);

int main()
{
    int a, b;
    fin>>n>>m;
    for (int i = 1; i <= n; i++)
    {
        fin>>x;
        v[i] = x;
    }
    build(1, 1, n);
    for (int i = 1; i <= m; i++)
    {
        fin>>c>>a>>b;
        if (c == 0)
        {
            fout<<query(1, 1, n, a, b)<<"\n";
        }
        else if (c == 1)
        {
            update(1, 1, n, a, b);
        }
    }
}

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

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

int query(int nod, int st, int dr, int l, int r)
{
    if(st >= l && dr <= r)
        return arb[nod];
    int rez = 0;
    int mij = (st + dr) / 2;
    if (l <= mij)
        rez = max(rez, query(nod * 2, st, mij, l, r));
    if (r >= mij + 1)
        rez = max(rez, query(nod * 2 + 1, mij + 1, dr, l, r));
    return rez;
}