Cod sursa(job #2502442)

Utilizator hunting_dogIrimia Alex hunting_dog Data 30 noiembrie 2019 20:51:03
Problema Arbori indexati binar Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.24 kb
#include <stdio.h>
#include <fstream>
#define NMAX 100000

using namespace std;

int n,v[NMAX],bit[NMAX+1];

int getSum(int i)
{
    int s=0;
    while(i)
    {
        s+=bit[i];
        i-=i&(-i);
    }

    return s;
}

void update(int i,int val)
{
    while(i<=n)
    {
        bit[i]+=val;
        i+=i&(-i);
    }
}

void buildTree()
{
    for(int i=0;i<n;++i)
        update(i+1,v[i]);
}

int findPos(int a)
{
    int s=0;
    for(int i=0;i<n;++i)
    {
        s+=v[i];
        if(s==a)
            return i+1;
    }
    return -1;
}

int main()
{
    freopen("aib.int","r",stdin);
    freopen("aib.out","w",stdout);
    int m;
    scanf("%i %i",&n,&m);
    for(int i=0;i<n;++i)
        scanf("%i",&v[i]);

    buildTree();
    while(m--)
    {
        int x,a,b;
        scanf("%i",&x);
        switch(x)
        {
        case 0:
            scanf("%i%i",&a,&b);
            update(a,b);
            v[a-1]+=b;
            break;
        case 1:
            scanf("%i%i",&a,&b);
            printf("%i\n",getSum(b)-getSum(a-1));
            break;
        case 2:
            scanf("%i",&a);
            printf("%i\n",findPos(a));
            break;
        }
    }

    return 0;
}