Cod sursa(job #2337402)

Utilizator HaesteinnSabau Florin Vlad Haesteinn Data 6 februarie 2019 12:47:05
Problema Arbori de intervale Scor 40
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.2 kb
#include<bits/stdc++.h>

using namespace std;
ifstream fin("arbint.in");
ofstream fout("arbint.out");
int n,q;
int arb[200005],v[100005];

inline int parent(int x)
{
    return x/2;
}

inline int right(int x)
{
    return 2*x+1;
}

inline int left(int x)
{
    return 2*x;
}

void build()
{
    for(int i=0;i<n;i++)
        fin>>v[i];
    while((n&(n-1))!=0)
        n++;
    for(int i=n;i<2*n;i++)
        arb[i]=v[i-n];

    for(int i=2*n-1;i>1;i--)
        arb[parent(i)]=max(arb[parent(i)],arb[i]);
}

void afisare()
{
    for(int i=1;i<2*n;i++)
        fout<<arb[i]<<" ";
    fout<<"\n";
}


void update(int poz,int a)
{
    poz+=n;
    arb[poz]=a;
    poz=parent(poz);
    while(poz!=0)
    {
        arb[poz]=max(arb[left(poz)],arb[right(poz)]);
        poz=parent(poz);
    }
}

int query(int a,int b,int k,int x,int y)
{
    if(b<x||a>y) return 0;
    if(a<=x&&y<=b) return arb[k];
    int d=(x+y)/2;
    return max(query(a,b,2*k,x,d),query(a,b,2*k+1,d+1,y));
}

int main()
{
    fin>>n>>q;
    build();
//    afisare();
    for(int i=0;i<q;i++)
    {
        int t,a,b;
        fin>>t>>a>>b;
        if(t) update(a-1,b);
 //       if(t) afisare();
        else fout<<query(a-1,b-1,1,0,n-1)<<"\n";
    }
    return 0;
}