Cod sursa(job #411514)

Utilizator NemultumituMatei Ionita Nemultumitu Data 4 martie 2010 22:34:21
Problema Arbori de intervale Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 0.95 kb
#include <cstdio>
int n,m;
int arb[400100];

int max(int a,int b)
{
	if (a>b)
		return a;
	return b;
}

int query(int nod,int st,int dr,int x,int y)
{
	if (x<=st&&y>=dr)
	{
		return arb[nod];
	}
	int r1=0,r2=0,m=(st+dr)/2;
	if (x<=m)
		r1=query(nod*2,st,m,x,y);
	if (y>=m+1)
		r2=query(nod*2+1,m+1,dr,x,y);
	return max(r1,r2);
}

void update(int nod,int st,int dr,int poz,int val)
{
	if (st==dr)
	{
		arb[nod]=val;
		return;
	}
	int m=(st+dr)/2;
	if (poz<=m)
		update(nod*2,st,m,poz,val);
	else
		update(nod*2+1,m+1,dr,poz,val);
	arb[nod]=max(arb[nod*2],arb[nod*2+1]);
}


int main()
{
	freopen ("arbint.in","r",stdin);
	freopen ("arbint.out","w",stdout);
	scanf("%d%d",&n,&m);
	int x,y,z;
	for (int i=1;i<=n;++i)
	{
		scanf("%d",&x);
		update(1,1,n,i,x);
	}
	for (int i=1;i<=m;++i)
	{
		scanf("%d%d%d",&x,&y,&z);
		if (x==0)
			printf("%d\n",query(1,1,n,y,z));
		else
			update(1,1,n,y,z);
	}
	return 0;
}