Cod sursa(job #2865744)

Utilizator ardutgamerAndrei Bancila ardutgamer Data 9 martie 2022 10:09:16
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.6 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

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

const int NMAX = 100005;
const int INF = 2e9;

int n, m;
int v[NMAX];
vector<int>arb;

void init(int n)
{
	int size = 1;
	while (size < n)
		size <<= 1;
	size <<= 1;
	arb.assign(size, 0);
}

int merge(int a, int b)
{
	return max(a, b);
}

void build(int nod, int st, int dr)
{
	if (st == dr)
	{
		arb[nod] = v[st];
		return;
	}
	int mij = ((st + dr) >> 1);
	build(2 * nod, st, mij);
	build(2 * nod + 1, mij + 1, dr);
	arb[nod] = merge(arb[2 * nod], arb[2 * nod + 1]);
}

void update(int nod, int st, int dr, int pos, int val)
{
	if (st == dr)
	{
		arb[nod] = val;
		return;
	}
	int mij = ((st + dr) >> 1);
	if(mij >= pos && pos >= st)
		update(2 * nod, st, mij, pos, val);
	else if(dr >= pos && pos >= mij+1)
		update(2 * nod + 1, mij + 1, dr, pos, val);
	arb[nod] = merge(arb[2 * nod], arb[2 * nod + 1]);
}

int query(int nod, int st, int dr, int x, int y)
{
	if (x <= st && dr <= y)
		return arb[nod];
	else if (y < st || x > dr)
		return 0;
	int mij = ((st + dr) >> 1);
	return merge(query(2 * nod, st, mij, x, y), query(2 * nod + 1, mij + 1, dr, x, y));
}

void read()
{
	fin >> n >> m;
	for (int i = 1; i <= n; i++)
		fin >> v[i];
	init(n);
	build(1, 1, n);
}

void solve()
{
	while (m--)
	{
		int tip, x, y;
		fin >> tip >> x >> y;
		if (tip == 0)
			fout << query(1, 1, n, x, y) << '\n';
		else
			update(1, 1, n, x, y);
	}
}

int main()
{
	read();
	solve();
	return 0;
}