Cod sursa(job #2289223)

Utilizator teotironTiron Teodor teotiron Data 24 noiembrie 2018 11:57:19
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.48 kb
#include <bits/stdc++.h>
#define NMAX 100005

using namespace std;

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

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

void build(int l, int r, int node)
{
    if(l==r)
        A[node]=v[l];
    else
    {
        int mid=(l+r)/2;
        build(l, mid, 2*node);
        build(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;
        int 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()
{
    fin>>n>>m;
    for(int i=1; i<=n; i++)
        fin>>v[i];
    build(1, n, 1);
    int op, x, y;
    for(int i=1; i<=m; i++)
    {
        fin>>op>>x>>y;
        if(op==0)
        {
            start=x;
            stop=y;
            fout<<query(1, n, 1)<<"\n";
        }
        else
        {
            v[x]=y;
            poz=x;
            update(1, n, 1);
        }
    }
    return 0;
}