Cod sursa(job #2051338)

Utilizator eragon0502Dumitrescu Dragos eragon0502 Data 28 octombrie 2017 20:18:06
Problema Arbori indexati binar Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.27 kb
#include <cstdio>

using namespace std;

int aib[200005],n,L=16;

int query(int x)
{
    int s=0;
    while(x!=0)
    {
        s+=aib[x];
        x-=(x&(-x));
    }
    return s;
}

int update(int x, int val)
{
    int p;
    while(x<=n)
    {
        aib[x]+=val;
        x+=(x&(-x));
    }
}

int caut(int k)
{
    int i=0,pas=1<<L;
    while(pas!=0)
    {
        if(query(i+pas)<=k&&i+pas<=n)
        {
            //k-=aib[i+pas];
            i+=pas;
        }
    pas/=2;
    }
    if(query(i)==k)
        return i;
    else
        return -1;
}

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

    scanf("%d %d",&n,&q);
    for(int i=1;i<=n;++i)
    {
        scanf("%d",&x);
        update(i,x);
    }

    for(int i=1;i<=q;++i)
    {
        scanf("%d",&p);
        if(p==0)
        {
            scanf("%d %d",&a,&b);
            update(a,b);
        }
        else
        if(p==1)
        {
            scanf("%d %d",&a,&b);
            b=query(b);
            --a;
            a=query(a);
            printf("%d\n",b-a);
        }
        else
        {
            scanf("%d",&a);
            printf("%d\n",caut(a));
        }
    }

    return 0;
}