Cod sursa(job #2614472)

Utilizator MarcGrecMarc Grec MarcGrec Data 11 mai 2020 19:49:37
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.93 kb
#define MAX_N 100000
#define LOG_MAX_N 16
#define INF 0x3f3f3f3f

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;

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

struct nodeinfo
{
	nodeinfo() :
		a(0),
		b(0),
		ma(0),
		u(0),
		v(0),
		f(0)
	{
	}
	
	int a, b, ma, u, v, f;
};

int n, m, node_val, A[MAX_N + 1], I[MAX_N + 1];
nodeinfo G[1 << (LOG_MAX_N + 2)];

void ConstructTree(int node, int a, int b);

void Set(int index, int val);

int MaxRange(int a, int b);
int Query(int node, int b);

int main()
{
	fin >> n >> m;
	for (int i = 1; i <= n; ++i)
	{
		fin >> A[i];
	}
	
	ConstructTree(++node_val, 1, n);
	
	for (int i = 0, q, a, b; i < m; ++i)
	{
		fin >> q >> a >> b;
		
		if (q == 0)
		{
			fout << MaxRange(a, b) << '\n';
		}
		else
		{
			Set(a, b);
		}
	}
	
	fin.close();
	fout.close();
	return 0;
}

void ConstructTree(int node, int a, int b)
{	
	G[node].a = a;
	G[node].b = b;
	
	if (a == b)
	{
		I[a]       = node;
		G[node].ma = A[a];
	}
	else
	{
		const int mid = (a + b) / 2;
		
		G[node].u     = ++node_val;
		G[node_val].f = node;
		ConstructTree(node_val, a, mid);
		
		G[node].v     = ++node_val;
		G[node_val].f = node;
		ConstructTree(node_val, mid + 1, b);
		
		G[node].ma = max(G[G[node].u].ma, G[G[node].v].ma);
	}
}

void Set(int index, int val)
{
	G[I[index]].ma = val;
	
	int node = G[I[index]].f;
	while (node != 0)
	{
		G[node].ma = max(G[G[node].u].ma, G[G[node].v].ma);
		node       = G[node].f;
	}
}

int MaxRange(int a, int b)
{	
	return Query(I[a], b);
}

int Query(int node, int b)
{
	int ma = G[node].ma;
	while (G[node].b < b)
	{
		ma = max(ma, G[node].ma);
		
		int fath = G[node].f;
		bool rg  = G[fath].v == node;
		if (!rg && (G[fath].b < b))
		{
			node = fath;
		}
		else
		{
			node = I[G[node].b + 1];
		}
	}
	
	return max(ma, G[node].ma);
}