Cod sursa(job #1120348)

Utilizator Al3ks1002Alex Cociorva Al3ks1002 Data 24 februarie 2014 23:21:05
Problema Arbori indexati binar Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.98 kb
#include<cstdio>
using namespace std;
const int nmax = 100005;
int n,m,i,x,aib[nmax],op,a,b;
void update(int poz,int val)
{
    for(int i=poz;i<=n;i+=i&(-i)) aib[i]+=val;
}
int sum(int poz)
{
    int r=0;
    for(int i=poz;i;i-=i&(-i)) r+=aib[i];
    return r;
}
int query(int x)
{
    int r=0,step,y=x;
    for(step=1;step<=n;step<<=1);
    for(;step;step>>=1)
        if(r+step<=n && aib[r+step]<x) {r+=step; x-=aib[r];}
    if(sum(++r)==y) return r;
    else return -1;
}
int main()
{
	freopen("aib.in","r",stdin);
	freopen("aib.out","w",stdout);
	scanf("%d%d",&n,&m);
	for(i=1;i<=n;i++)
	{
	    scanf("%d",&x);
	    update(i,x);
	}
	for(;m;m--)
	{
	    scanf("%d",&op);
	    if(op==0)
	    {
	        scanf("%d%d",&a,&b);
	        update(a,b);
	    }
	    else if(op==1)
	    {
	        scanf("%d%d",&a,&b);
	        printf("%d\n",sum(b)-sum(a-1));
	    }
	    else
	    {
	        scanf("%d",&a);
	        printf("%d\n",query(a));
	    }
	}
	return 0;
}