Cod sursa(job #1626512)

Utilizator fetti_danutzdezactivat fetti_danutz Data 3 martie 2016 09:43:05
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.05 kb
#include <fstream>
using namespace std;

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

const int MaxN = 100000;
int st[4 * MaxN];
int n, m, op, a, b, p, val;
int vmax = -1;

void Update(int x, int l, int r);
void Query(int x, int l, int r);

int main()
{
	fin >> n >> m;

	for (int i = 1; i <= n; ++i)
	{
		fin >> val;
		p = i;
		Update(1, 1, n);
	}
	
	for (int i = 0; i < m; ++i)
	{
		fin >> op >> a >> b;
		if ( op == 0 )
		{
			vmax = -1;
			Query(1, 1, n);
			fout << vmax << '\n';
		}
		else
		{
			p = a; val = b;
			Update(1, 1, n);
		}
	}
	
	fin.close();
	fout.close();
	return 0;
}

void Update(int x, int l, int r) // update pe element
{
	if ( l == r )
	{
		st[x] = val;
		return;
	}
	
	int m = (l + r) / 2;
	if ( p <= m )
		Update(2 * x, l, m);
	else
		Update(2 * x + 1, m + 1, r);
		
	st[x] = max(st[2 * x], st[2 * x + 1]);
}

void Query(int x, int l, int r)
{
	if ( a <= l && r <= b)
	{
		vmax = max(vmax, st[x]);
		return;
	}
	
	
	int m = ( l + r) / 2;
	if ( a <= m )
		Query(2 * x, l, m);
	
	if ( m < b )
		Query(2 * x + 1, m + 1, r);
}