Cod sursa(job #2106682)

Utilizator anca.sotirAnca Sotir anca.sotir Data 16 ianuarie 2018 01:48:48
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.21 kb
#include <iostream>
#include <fstream>
using namespace std;
ifstream f("arbint.in");
ofstream g("arbint.out");
int AI[400000];

void update(int st,int dr,int nod, int poz, int val)
{
    if(st==dr-1 && st==poz)
        {
            AI[nod]=val;
            return;
        }
    int mij=st+(dr-st)/2;
    if(poz<mij)
        update(st, mij, nod*2, poz, val);
    else update (mij, dr, nod*2+1, poz, val);
    AI[nod]=max(AI[nod*2],AI[nod*2+1]);
}

int query(int st, int dr, int nod, int l, int r)
{
    if( st>=r || dr<=l) ///intersectia intervalelor e vida
        return -1;
    if( st>=l && dr<=r) /// [st,dr) e inclus sau egal cu [l,r)
        return AI[nod];
    int mij=st+(dr-st)/2;
    return max(query(st,mij,nod*2,l,r),query(mij,dr,nod*2+1,l,r));
}

int main()
{
    int m,n;
    f>>n>>m;
    for(int i=1;i<=n;++i)
    {
        int x;
        f>>x;
        update(1,n+1,1,i,x);
    }
    for(int i=1;i<=m;++i)
    {
        ///op=0 => query max interval [x,y]
        ///op=1 => update element de pe poz x cu val y
        int op,x,y;
        f>>op>>x>>y;
        if(op==0)
            g<<query(1,n+1,1,x,y+1)<<'\n';
        else update(1,n+1,1,x,y);
    }
    return 0;
}