Cod sursa(job #2314148)

Utilizator IordachescuAncaFMI Iordachescu Anca Mihaela IordachescuAnca Data 7 ianuarie 2019 23:00:46
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.9 kb
#include<fstream>
#define NMAX 100007
using namespace std;

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

int ai[4*NMAX],v[NMAX], M, N;

void build(int nod, int st, int dr)
{
    if (st == dr)
    {
        ai[nod] = v[st];
        return;
    }
    else
    {
        int mij = (st + dr)/2;
        build(2 * nod, st, mij);
        build(2 * nod + 1, mij + 1, dr);
        ai[nod] = max(ai[2 * nod], ai[2 * nod + 1]);
    }
}

void update(int nod, int pozitie, int val, int st, int dr)
{
    if (st == dr)
    {
        ai[nod] = val;
    }
    else
    {
        int mij = (st + dr)/2;
        if (pozitie <= mij)
        {
            update(2 * nod, pozitie, val, st, mij);
        }
        else
        {
            update(2 * nod + 1, pozitie, val, mij + 1, dr);
        }
        ai[nod] = max(ai[2 * nod], ai[2 * nod + 1]);
    }
}

int maxim(int nod, int st, int dr, int a, int b)
{
    if (dr < a || b < st) //intervale disjuncte
    {
        return 0;
    }
    else
    {
        if(a <= st && dr <= b) //interval inclus complet in alt interval
        {
            return ai[nod];
        }
        else
        {
            int mij = (st + dr)/2;
            int sum1 = maxim(2 * nod, st, mij, a, b); // interval inclus partial in alt interval
            int sum2 = maxim(2 * nod + 1, mij + 1, dr, a, b);

            return max(sum1, sum2);
        }
    }
}

int main()
{
    fin >> N >> M;

    int i;
    for (i = 1; i <= N; i++)
    {
        fin >> v[i];
    }
    build(1,1,N);

    for(i = 1; i <= M; i++)
    {
        int a, b, digit ;
        fin >> digit >> a >> b;

        if (digit == 0)
        {
            fout << maxim(1, 1, N, a, b)<<"\n";
        }

        if(digit == 1)
        {
            update(1, a, b, 1, N);
        }
    }

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

    return 0;
}