Cod sursa(job #2289224)

Utilizator tudor.bujdeiTudor Bujdei-Leonte tudor.bujdei Data 24 noiembrie 2018 11:57:58
Problema Arbori de intervale Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.39 kb
#include <bits/stdc++.h>
#define NMAX 100050

using namespace std;

ifstream ifs("arb.in");
ofstream ofs("arb.out");

int v[NMAX], a[NMAX*4], n, m, poz, start, stop;

void arbore(int l, int r, int node)
{
    if(l==r) a[node]=v[l];
    else
    {
        int mid=(l+r)/2;
        arbore(l, mid, 2*node);
        arbore(mid+1, r, 2*node+1);

        a[node]=max(a[2*node], a[2*node+1]);
    }
}

void update(int l, int r, int node)
{
    if(l==r) a[node]=v[l];
    else
    {
        int mid=(l+r)/2;
        if(poz<=mid) update(l, mid, 2*node);
        else update(mid+1, r, 2*node+1);

        a[node]=max(a[2*node], a[2*node+1]);
    }
}

int query(int l, int r, int node)
{
    if(start<=l&&stop>=r) return a[node];
    else
    {
        int mid=(l+r)/2, maxl=INT_MIN, maxr=INT_MIN;

        if(start<=mid) maxl=query(l, mid, 2*node);
        if(mid+1<=stop) maxr=query(mid+1, r, 2*node+1);

        return max(maxl, maxr);
    }
}

int main()
{

    ifs>>n>>m;
    for(int i=0;i<=n;i++) ifs>>v[i];

    arbore(1, n, 1);

    int op, x, y;
    for(int i=1;i<=m;i++)
    {
        ifs>>op>>x>>y;
        if(op==0)
        {
            start = x;
            stop = y;
            ofs<<query(1, n, 1)<<"\n";
        }
        else
        {
            v[x]=y;
            poz=x;
            update(1, n, 1);
        }
    }


    return 0;
}