Cod sursa(job #2104200)

Utilizator DavidLDavid Lauran DavidL Data 11 ianuarie 2018 13:13:46
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.32 kb
#include <fstream>
#define MAX 100005
using namespace std;
ifstream fi("arbint.in");
ofstream fo("arbint.out");

int A[5*MAX];
int pos,val;
int st,dr,maxim;
int n,m;

void update(int nod,int l,int r)
{
    if (l==r)
    {
        A[nod]=val;
        return;
    }

    /// mergem la copii
    int mij=(l+r)/2;
    if (pos<=mij) /// mergem la copilul din stanga
        update(2*nod,l,mij);
    else /// mergem la copilul din dreapta
        update(2*nod+1,mij+1,r);

    A[nod]=max(A[2*nod],A[2*nod+1]);
}

void query(int nod,int l,int r)
{
    /// cautam intre st si dr
    if (st<=l && r<=dr) /// nodul e in intregime in [st,dr]
    {
        maxim=max(maxim,A[nod]);
        return;
    }
    int mij=(l+r)/2;
    if (st<=mij)
        query(2*nod,l,mij);
    if (mij<dr)
        query(2*nod+1,mij+1,r);
}

int main()
{
    fi>>n>>m;
    for (int i=1; i<=n; i++)
    {
        int x;
        fi>>x;
        pos=i,val=x;
        update(1,1,n);
    }
    for (int i=1; i<=m; i++)
    {
        int c,a,b;
        fi>>c>>a>>b;
        if (c==0)
        {
            maxim=-1;
            st=a,dr=b;

            query(1,1,n);

            fo<<maxim<<"\n";
        }
        else
        {
            pos=a,val=b;
            update(1,1,n);
        }
    }

    return 0;
}