Cod sursa(job #2803085)

Utilizator filiptudose2007Tudose Filip filiptudose2007 Data 19 noiembrie 2021 14:08:28
Problema Arbori indexati binar Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.17 kb
#include <bits/stdc++.h>
using namespace std;
int n,m,a,b,aib[100005],v[100005],c,i;
int ub(int x)
{
    return (x&(-x));
}
void add(int a,int b)
{
    for(int i=a; i<=n; i+=ub(i))
        aib[i]+=b;
}
int Sum(int x)
{
    int s=0;
    for(int i=x; i>=1; i-=ub(i))
        s+=aib[i];
    return s;
}
int cbin(int x, int n)
{
    int st=1,dr=n,mij=0,s=0,p=0;
    while(st<=dr)
    {
        mij=(st+dr)/2;
        s=Sum(mij);
        if(s==x)p=mij;

        if(s>=x)dr=mij-1;
        else st=mij+1;
    }
    if(p==0)return -1;
    else return p;
}
int main()
{
    freopen("aib.in","r",stdin);
    freopen("aib.out","w",stdout);
    cin.sync_with_stdio(false);
    cin.tie(0);
    cin>>n>>m;
    int x;
    for(i=1; i<=n; ++i)
    {
        cin>>x;
        add(i,x);
    }
    for(i=1; i<=m; ++i)
    {
        cin>>c;
        if(c==0)
        {
            cin>>a>>b;
            add(a,b);
        }
        else if(c==1)
        {
            cin>>a>>b;
            cout<<Sum(b)-Sum(a-1)<<'\n';
        }
        else if(c==2)
        {
            cin>>a;
            cout<<cbin(a,n)<<'\n';
        }
    }
    return 0;
}