Cod sursa(job #1209461)

Utilizator Paula-ElenaPaula-Elena Margarit Paula-Elena Data 17 iulie 2014 19:10:32
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.34 kb
#include<fstream>
using namespace std;

ifstream fin("arbint.in");
ofstream fout("arbint.out");

const int MAXN = 300010;
int arb[MAXN], x, a, b, M, N, val, poz;

int maxim(int a, int b){
    if(a > b)
        return a;
    else
        return b;
}

int query(int, int, int);
void update(int, int, int);

void update(int p, int st, int dr)
{
    if(st == dr){
        arb[p] = val;
        return;
    }
    int mij = (st+dr)/2;
    if(poz <= mij)
        update(2*p, st, mij);
    else
        update(2*p+1, mij+1, dr);
    arb[p] = maxim(arb[2*p], arb[2*p+1]);
}

int query(int p, int st, int dr)
{
    if(a<=st && dr<=b)
        return arb[p];
    int mij = (st + dr) >> 1, m1 = -1, m2 = -1;
    if(a <= mij)
        m1 = query(2*p, st, mij);
    if(mij < b)
        m2 = query(2*p+1, mij+1, dr);
    return maxim(m1, m2);
}

int main()
{
    int i, nrQ = 0;
    fin >> N >> M;

    for(i=1; i<=N; ++i)
    {
        fin >> x ;
        poz = i;
        val = x;
        update(1, 1, N);
    }

    for(i=1; i<=M; ++i)
    {
        fin >> x >> a >> b;
        if(x == 0){
            fout << query(1, 1, N) << "\n";
        }
        else
        {
            poz = a;
            val = b;
            update(1, 1, N);
        }
    }

    fin.close();
    fout.close();

    return 0;
}