Cod sursa(job #2444719)

Utilizator petrisorvmyVamanu Petru Gabriel petrisorvmy Data 1 august 2019 11:06:09
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.55 kb
#include <fstream>
#define NMAX 100005
using namespace std;

ifstream f("arbint.in");
ofstream g("arbint.out");
int n,q, v[NMAX], aint[4*NMAX],task,a,b,ans;
void build(int nod, int st, int dr)
{
    if(st == dr)
    {
        aint[nod] = v[st];
        return;
    }
    int mid = st + (dr - st) / 2;
    build(nod << 1 , st , mid);
    build(nod << 1 | 1, mid +  1 , dr);
    aint[nod] = max(aint[nod << 1], aint[nod << 1 | 1]);
}
void update(int nod, int st, int dr, int poz, int val)
{
    if(poz < st || poz > dr)
        return;
    if(st == dr && st == poz)
    {
        aint[nod] = val;
        return;
    }
    int mid = st + (dr - st) / 2;
    update(nod << 1, st , mid, poz, val);
    update(nod << 1 | 1, mid + 1 , dr, poz, val);
    aint[nod] = max(aint[nod << 1], aint[nod << 1 | 1]);
}
void query(int nod, int st, int dr, int left, int right)
{
    if(left <= st && dr <= right)
    {
        ans = max(ans, aint[nod]);
        return ;
    }
    int mid = st + (dr - st) / 2;
    if(left <= mid)
        query(nod << 1, st, mid, left, right) ;
    if(right > mid)
        query(nod << 1 | 1, mid + 1, dr, left, right);
}
int main()
{
    f >> n >> q;
    for(int i = 1; i <= n; ++i)
        f >> v[i];
    build(1,1,n);
    for(int i = 1; i <= q; ++i)
    {
        f >> task >> a >> b;
        if(task == 0)
        {
            ans = 0;
            query(1,1,n,a,b);
            g << ans << '\n';
        }
        else
            update(1,1,n,a,b);
    }

    f.close(); g.close();
    return 0;
}