Cod sursa(job #1045829)

Utilizator alexpascadiAlexandru Pascadi alexpascadi Data 2 decembrie 2013 09:06:26
Problema Arbori de intervale Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.32 kb
#include <stdio.h>
#include <fstream>
using namespace std;

const int N=100001;
const int P=1<<18;
int t[P],v[N];
int n,m,a,b,val,poz;

int query(int p, int st, int dr)
{
    if(a<=st && dr<=b)
        return t[p];
    int rez=-1, aux, m=(st+dr)>>1;
    if(a<=m)
    {
        aux=query(p*2,st,m);
        if(aux>rez) rez=aux;
    }
    if(m+1<=b)
    {
        aux=query(p*2+1,m+1,dr);
        if(aux>rez) rez=aux;
    }
    return rez;
}

void update(int p, int st, int dr)
{
    if(st==dr)
    {
        t[p]=val;
    }
    else
    {
        int m=st+dr; m>>=1;
        if(poz<=m)
        {
            update(2*p,st,m);
        }
        else
        {
            update(2*p+1,m+1,dr);
        }
        if(t[2*p]>t[2*p+1]) t[p]=t[2*p];
        else t[p]=t[2*p+1];
    }
}

int main()
{
    ifstream in("arbint.in");
    FILE *out;
    out=fopen("arbint.out","w");
    in>>n>>m;
    int i,x;
    for(i=1;i<=n;i++)
        in>>v[i];
    for(i=1;i<=n;i++)
    {
        poz=i; val=v[i];
        update(1,1,n);
    }
    for(i=1;i<=m;i++)
    {
        in>>x;
        if(x==0)
        {
            in>>a>>b;
            fprintf(out,"%d\n",query(1,1,n));
        }
        else
        {
            in>>poz>>val;
            update(1,1,n);
        }
    }
    return 0;
}