Cod sursa(job #885188)

Utilizator NistorSergiuNistor Sergiu NistorSergiu Data 21 februarie 2013 18:25:59
Problema Arbori de intervale Scor 40
Compilator cpp Status done
Runda Arhiva educationala Marime 1.08 kb
#include<cstdio>
using namespace std;
int maxarb[200001];
int maxim(int a, int b)
{
	if(a>b)
		return a;
	return b;
}
void update(int nod, int st, int dr, int poz, int val)
{
	int mij;
	if(st==dr)
		maxarb[nod]=val;
	else
	{
		mij=(st+dr)/2;
		if(poz<=mij)
			update(2*nod,st,mij,poz,val);
		else
			update(2*nod+1,mij+1,dr,poz,val);
		maxarb[nod]=maxim(maxarb[2*nod],maxarb[2*nod+1]);
	}
}
int query(int nod, int st, int dr, int start, int final)
{
	int mij,v1=-1,v2=-1;
	if((st>=start)&&(dr<=final))
		return maxarb[nod];
	mij=(st+dr)/2;
	if(start<=mij)
		v1=query(2*nod,st,mij,start,final);
	if(final>mij)
		v2=query(2*nod+1,mij+1,dr,start,final);
	return maxim(v1,v2);
}
int main()
{
	int n,m,i,x,a,b;
	freopen("arbint.in","r",stdin);
	freopen("arbint.out","w",stdout);
	scanf("%d %d\n",&n,&m);
	for(i=1;i<=n;i++)
	{
		scanf("%d ",&x);
		update(1,1,n,i,x);
	}
	
	for(i=1;i<=m;i++)
	{
		scanf("%d %d %d\n",&x,&a,&b);
		if(x==0)
			printf("%d\n",query(1,1,n,a,b));
		else
			update(1,1,n,a,b);
	}
	fclose(stdin);
	fclose(stdout);
	return 0;
}