Cod sursa(job #2922540)

Utilizator raresgherasaRares Gherasa raresgherasa Data 8 septembrie 2022 20:39:33
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.17 kb
#include <bits/stdc++.h>

using namespace std;

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

const int NM = 1e5 + 5;

int arb[4 * NM];
int n, m, ans;

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

void query (int nod, int st, int dr, int Qst, int Qdr){
  if (Qst <= st && dr <= Qdr){
    ans = max(ans, arb[nod]);
  }
  else{
    int mid = (st + dr) / 2;
    if (Qst <= mid){
      query(2 * nod, st, mid, Qst, Qdr);
    }
    if (mid + 1 <= Qdr){
      query(2 * nod + 1, mid + 1, dr, Qst, Qdr);
    }
  }
}

int main(){
  fin >> n >> m;
  for (int i = 1; i <= n; i++){
    int x; fin >> x;
    update(1, 1, n, i, x);
  }
  while (m--){
    int op, l, r; fin >> op >> l >> r;
    if (op == 1){
      update(1, 1, n, l, r);
    }
    else{
      ans = 0;
      query(1, 1, n, l, r);
      fout << ans << '\n';
    }
  }
}