Cod sursa(job #2219587)

Utilizator dfettiDaniel Fetti dfetti Data 9 iulie 2018 13:32:36
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.37 kb
#include <fstream>
using namespace std;
 
ifstream fin("arbint.in");
ofstream fout("arbint.out");
 
const int MaxN = 100000;
int st[4 * MaxN];
int n, m, op, a, b, p, val;
int vmax = -1;
 
void Update(int x, int l, int r);
void Query(int x, int l, int r);
 
int main()
{
    fin >> n >> m;
 
    for (int i = 1; i <= n; ++i)
    {
        fin >> val;
        p = i;
        Update(1, 1, n);
    }
     
    for (int i = 0; i < m; ++i)
    {
        fin >> op >> a >> b;
        if ( op == 0 )
        {
            vmax = -1;
            Query(1, 1, n);
            fout << vmax << '\n';
        }
        else
        {
            p = a; val = b;
            Update(1, 1, n);
        }
    }
     
    fin.close();
    fout.close();
    return 0;
}
 
void Update(int x, int l, int r) // update pe element
{
    if ( l == r )
    {
        st[x] = val;
        return;
    }
     
    int m = (l + r) / 2;
    if ( p <= m )
        Update(2 * x, l, m);
    else
        Update(2 * x + 1, m + 1, r);
         
    st[x] = max(st[2 * x], st[2 * x + 1]);
}
 
void Query(int x, int l, int r)
{
    if ( a <= l && r <= b)
    {
        vmax = max(vmax, st[x]);
        return;
    }
     
     
    int m = ( l + r) / 2;
    if ( a <= m )
        Query(2 * x, l, m);
     
    if ( m < b )
        Query(2 * x + 1, m + 1, r);
}