Cod sursa(job #214386)

Utilizator RobybrasovRobert Hangu Robybrasov Data 14 octombrie 2008 00:06:13
Problema Arbori de intervale Scor 40
Compilator cpp Status done
Runda Arhiva educationala Marime 1.38 kb
#include <stdio.h>

int V[100010],A[200020],n,i,st,dr,mmax,poz,elem,m,a,b,nr;

// A - arborele de intervale
// V - vectorul cu elementele

int max(int a, int b)
{
    return (a>b)?a:b;
}


void query(int nod, int a, int b)
{
    if (st<=a && dr>=b) mmax=max(mmax,A[nod]);
    else
    {
        int m=(a+b)/2;
        if (st<=m) query(nod*2,a,m);
        if (dr>m) query(nod*2+1,m+1,b);
    }
}

void build(int nod, int a, int b)
{
    if (a==b) A[nod]=V[a];
    else
    {
        int m=(a+b)/2;
        build(nod*2,a,m);
        build(nod*2+1,m+1,b);
        A[nod]=max(A[nod*2],A[nod*2+1]);
    }
}

void update(int nod, int a, int b)
{
    if (a==b) A[nod]=elem;
    else
    {
        int m=(a+b)/2;
        if (poz<=m) update(nod*2,a,m);
        else        update(nod*2+1,m+1,b);
        A[nod]=max(A[nod*2],A[nod*2+1]);
    }
}

int main()
{
    freopen("arbint.in","r",stdin);
    freopen("arbint.out","w",stdout);
    scanf("%d %d\n",&n,&m);
    for (i=1; i<=n; i++) scanf("%d ",&V[i]);
    build(1,1,n);
    for (int k=1; k<=m; k++)
    {
        scanf("%d %d %d\n",&nr,&a,&b);
        if (nr)
        {
            poz=a; elem=b;
            update(1,1,n);
        }
        else
        {
            st=a; dr=b;
            mmax=0;
            query(1,1,n);
            printf("%d\n",mmax);
        }
    }

    return 0;
}