Cod sursa(job #404029)

Utilizator GotenAmza Catalin Goten Data 25 februarie 2010 18:13:57
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.76 kb
#include<fstream.h>
int aib[100100],n,u;
void plus(int i, int x)
{
	while(i<=n)
	{
		aib[i]+=x;
		i=(i|(i-1))+1;
	}
}
int sum(int i)
{
	int s=0;
	while(i)
	{
		s+=aib[i];
		i&=(i-1);
	}
	return s;
}
int query(int x)
{
	int i=0,p=u;
	while(p)
	{
		if(i+p<=n)
			if(x>=aib[i+p])
			{
				x-=aib[i+p];
				i+=p;
				if(!x)
					return i;
			}
		p>>=1;
	}
	return -1;
}
int main()
{
	int m,i,x,op,a,b;
	ifstream f("aib.in");
	ofstream g("aib.out");
	f>>n>>m;
	u=1;
	while(u<n)
		u<<=1;
	for(i=1;i<=n;i++)
	{
		f>>x;
		plus(i,x);
	}
	while(m--)
	{
		f>>op;
		if(op==2)
		{
			f>>a;	
			g<<query(a)<<'\n';
		}
		else
		{
			f>>a>>b;
			if(!op)
				plus(a,b);
			else
				g<<sum(b)-sum(a-1)<<'\n';
		}
	}
	return 0;
}