Cod sursa(job #1041574)

Utilizator alexpascadiAlexandru Pascadi alexpascadi Data 25 noiembrie 2013 22:17:20
Problema Arbori de intervale Scor 40
Compilator cpp Status done
Runda Arhiva educationala Marime 1.36 kb
#include <stdio.h>

using namespace std;

const int N=100001;
int t[2*N],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)/2;
    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)/2;
        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()
{
    FILE *in,*out;
    in=fopen("arbint.in","r");
    out=fopen("arbint.out","w");
    fscanf(in,"%d%d",&n,&m);
    int i,x;
    for(i=1;i<=n;i++)
        fscanf(in,"%d",&v[i]);
    for(i=1;i<=n;i++)
    {
        poz=i; val=v[i];
        update(1,1,n);
    }
    for(i=1;i<=m;i++)
    {
        fscanf(in,"%d",&x);
        if(x==0)
        {
            fscanf(in,"%d%d",&a,&b);
            fprintf(out,"%d\n",query(1,1,n));
        }
        else
        {
            fscanf(in,"%d%d",&poz,&val);
            update(1,1,n);
        }
    }
    return 0;
}