Cod sursa(job #2122468)

Utilizator cicero23catalin viorel cicero23 Data 5 februarie 2018 10:04:38
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.91 kb
#include <iostream>
#include <fstream>
#define N 100001
using namespace std;
ifstream f("arbint.in");
ofstream g("arbint.out");
int v[N],aint[N<<1];
int n;
void build()
{
    int i;
    for(i=1;i<=n;i++)
        aint[n+i-1]=v[i];
    for(i=n-1;i>=0;i--)
        aint[i]=max(aint[i<<1],aint[i<<1|1]);
}
void update(int p,int x)
{
    int i;
    aint[p+n-1]=x;
    for(i=(p+n-1)/2;i>0;i>>=1)
    {
        aint[i]=max(aint[i<<1],aint[i<<1|1]);
    }
}
int querry(int a,int b)
{
    a+=n-1;
    b+=n;
    int res=0;
    for(;a<b;a>>=1,b>>=1)
    {
        if(a&1) res=max(res,aint[a++]);
        if(b&1) res=max(res,aint[--b]);
    }
    return res;
}
int main()
{
    int i,m,q,x,y;
    f>>n>>m;
    for(i=1;i<=n;i++)
        f>>v[i];
    build();
    for(i=1;i<=m;i++)
    {
        f>>q>>x>>y;
        if(q==0) g<<querry(x,y)<<'\n';
        else update(x,y);
    }
    return 0;
}