Cod sursa(job #1936675)

Utilizator matystroiaStroia Matei matystroia Data 23 martie 2017 11:56:12
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.09 kb
#include <fstream>
using namespace std;

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

const int N=100001;

int n, m, ai[4*N];

void update(int nod, int l, int r, int i, int x)
{
    if(l==r)
    {
        ai[nod]=x;
        return;
    }

    int mid=(l+r)/2;
    if(i<=mid)
        update(2*nod, l, mid, i, x);
    else
        update(2*nod+1, mid+1, r, i, x);

    ai[nod]=max(ai[2*nod], ai[2*nod+1]);
}

int query(int nod, int l, int r, pair<int,int> iv)
{
    if(iv.first<=l&&r<=iv.second)
        return ai[nod];

    int mid=(l+r)/2, m1=0, m2=0;
    if(iv.first<=mid)
        m1=query(2*nod, l, mid, iv);
    if(mid<iv.second)
        m2=query(2*nod+1, mid+1, r, iv);

    return max(m1, m2);
}

int main()
{
    fin>>n>>m;
    for(int i=1;i<=n;++i)
    {
        int x; fin>>x;
        update(1, 1, n, i, x);
    }

    for(int i=0;i<m;++i)
    {
        int x, a, b;
        fin>>x>>a>>b;

        if(x==0)
            fout<<query(1, 1, n, make_pair(a, b))<<'\n';
        else
            update(1, 1, n, a, b);
    }

    return 0;
}