Cod sursa(job #1653893)

Utilizator cosmin.pascaruPascaru Cosmin cosmin.pascaru Data 16 martie 2016 17:54:26
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.36 kb
#include <iostream>
#include <fstream>
#include <cstring>
#include <algorithm>

#define NMAX 100005

using namespace std;

class ArbInt
{
private:
	int tree[NMAX * 4];

public:
	ArbInt(int dim)
	{
		memset(tree, 0, sizeof(tree));
	};
	void Update(int node, int st, int dr, int poz, int val)
	{
		if (st >= dr)
		{
			tree[node] = val;
			return;
		}

		int mij = st + ((dr - st) >> 1);
		if (poz <= mij)
			Update(2 * node, st, mij, poz, val);
		else
			Update(2 * node + 1, mij + 1, dr, poz, val);

		tree[node] = max(tree[2 * node], tree[2 * node + 1]);
	}
	int Query(int node, int st, int dr, int a, int b)
	{
		if (a <= st && dr <= b) return tree[node];

		int mij = st + ((dr - st) >> 1);
		int resLeft = 0, resRight = 0;
		if (a <= mij) resLeft = Query(2 * node, st, mij, a, b);
		if (b > mij) resRight = Query(2 * node + 1, mij + 1, dr, a, b);

		return max(resLeft, resRight);
	}
};

ArbInt arb(NMAX);

int main()
{
	ios_base::sync_with_stdio(false);

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

	int n, m;
	fin >> n >> m;
	
	for (int i = 1; i <= n; ++i)
	{
		int x;
		fin >> x;
		arb.Update(1, 1, n, i, x);
	}
	for (int i = 1; i <= m; ++i)
	{
		int t, a, b;
		fin >> t >> a >> b;
		if (t == 0)
			fout << arb.Query(1, 1, n, a, b) << '\n';
		else
			arb.Update(1, 1, n, a, b);
	}
	return 0;
}