Cod sursa(job #1248174)

Utilizator bciobanuBogdan Ciobanu bciobanu Data 24 octombrie 2014 19:12:02
Problema Arbori indexati binar Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.19 kb
#include <cstdio>
using namespace std;
const int LIMIT = 100005;
int AIB[LIMIT], N;
inline int lsb(int a)
{
    return (a & (a - 1)) ^ a;
}
void update(int pos, int val)
{
    for(; pos <= N; pos += lsb(pos))
        AIB[pos] += val;
}
int query(int pos)
{
    int s = 0;
    for(; pos; pos -= lsb(pos))
        s += AIB[pos];
    return s;
}
int SEARCH(int a)
{
    int i, pas = N;
    while(pas & (pas - 1))
        pas &= (pas - 1);
    for(i = 0; pas; pas >>= 1)
        if(i + pas <= N && query(i + pas) < a)
            i += pas;
    return i + 1;
}
int main()
{
    freopen("aib.in", "r", stdin);
    freopen("aib.out", "w", stdout);
    int M, X, i, a, b;
    scanf("%d %d", &N, &M);
    for(i = 1; i <= N; ++i)
    {
        scanf("%d", &X);
        update(i, X);
    }
    while(M--)
    {
        scanf("%d %d", &X, &a);
        if(!X)
        {
            scanf("%d", &b);
            update(a, b);
        }
        else if(X == 1)
        {
            scanf("%d", &b);
            printf("%d\n", query(b) - query(a - 1));
        }
        else
            printf("%d\n", SEARCH(a));
    }
    fclose(stdin);
    fclose(stdout);
    return 0;
}