Cod sursa(job #569260)

Utilizator b_polarAgape Mihai b_polar Data 1 aprilie 2011 11:03:30
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.84 kb
#include <cstdio>
#include <iostream>
#include <vector>

using namespace std;
const int NMAX=100001;

int N,Q;
vector<int> bit(NMAX,0);

void update(int poz,int add)
{
	while(poz<=N)
		bit[poz]+=add,
		poz+=(poz&-poz);
}

int query(int poz)
{
	int s=0;
	while(poz>0)
		s+=bit[poz],
		poz-=(poz&-poz);
	return s;
}

int search(int s)
{
	int ls=0,ld=N+1,pm;
	for(pm=(ls+ld)>>1;pm>ls&&pm<ld;pm=(ls+ld)>>1)
	{
		int vm=query(pm);
		if(vm>s)ld=pm;
		else if(vm<s)ls=pm;
		else return pm;
	}
	return -1;
}


int main()
{
	int op,a,b;
	freopen("aib.in","r",stdin);
	freopen("aib.out","w",stdout);

	cin>>N>>Q;
	for(int i=1,add;i<=N;i++)
	{
		scanf("%d",&add);
		update(i,add);
	}

	while(Q--)
	{
		scanf("%d %d",&op,&a);
		if(op==2)
			printf("%d\n",search(a));
		else
			if(scanf("%d",&b)&&op==1)
				printf("%d\n",query(b)-query(a-1));
			else
				update(a,b);
	}
}