Cod sursa(job #2743274)

Utilizator EZ4ENCEAleksi Jalli EZ4ENCE Data 22 aprilie 2021 19:24:24
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.68 kb
#include <iostream>
#include <fstream>
#define NMAX 100000

using namespace std;

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

int aint[NMAX * 4 + 1], v[NMAX + 1];

int join(int a, int b) {
  return a < b ? b : a;
}

void build(int poznode, int l, int r) {
  if (l == r) {
    aint[poznode] = v[l];
    return;
  }

  int mid = (l + r) / 2;
  build(poznode * 2, l, mid);
  build(poznode * 2 + 1, mid + 1, r);

  aint[poznode] = join(aint[poznode * 2], aint[poznode * 2 + 1]);
}

void update(int poznode, int l, int r, int poz, int val) { /// elementul de pe pozitia poz ia valoarea val
  if (l == r) {
    aint[poznode] = val;
    return;
  }

  int mid = (l + r) / 2;
  if (poz <= mid)
    update(poznode * 2, l, mid, poz, val);
  else
    update(poznode * 2 + 1, mid + 1, r, poz, val);

  aint[poznode] = join(aint[poznode * 2], aint[poznode * 2 + 1]);
}

int query(int poznode, int l, int r, int a, int b) {
  int val;
  if (l >= a && r <= b)
    return aint[poznode];

  int mid = (l + r) / 2;

  if (a <= mid)
    val = query(poznode * 2, l, mid, a, b);
  if (b >= mid + 1 && a <= mid)
    val = join(val, query(poznode * 2 + 1, mid + 1, r, a, b));
  else if (b >= mid + 1)
    val = query(poznode * 2 + 1, mid + 1, r, a, b);

  return val;
}

int main() {
  int n, q, i, op, a, b, poz, val;
  fin >> n >> q;

  for (i = 1; i <= n; i++)
    fin >> v[i];


  build(1, 1, n);
  while (q--) {
    fin >> op;
    if (op == 0) {
      fin >> a >> b;
      fout << query(1, 1, n, a, b) << "\n";
    }
    else {
      fin >> poz >> val;
      update(1, 1, n, poz, val);
      //cout << aint[5] << "\n";
    }
  }
  return 0;
}