Cod sursa(job #2579143)

Utilizator doNotRecallRasa Andrei doNotRecall Data 11 martie 2020 23:52:13
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.27 kb
#include<fstream>
#include<algorithm>

using namespace std;

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

int A[400005], x[100005], n, m;
int qs, op, a, b;

void build(int st, int dr, int nod)
{
	if (st == dr)
	{
		A[nod] = x[st];
		return;
	}
	int mij = st + (dr - st) / 2;
	build(st, mij, 2 * nod);
	build(mij + 1, dr, 2 * nod + 1);
	A[nod] = max(A[2 * nod], A[2 * nod + 1]);
}

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

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

int main()
{
	in >> n >> m;
	for (int i = 1; i <= n; i++)
	{
		in >> x[i];
	}

	build(1, n, 1);
	for (int i = 1; i <= m; i++)
	{
		in >> op >> a >> b;
		if (op == 0)
		{
			qs = 0;
			query(1, n, 1, a, b);
			out << qs << "\n";
		}
		else
		{
			update(1, n, 1, a, b);
		}
	}

	return 0;
}