Cod sursa(job #1250927)

Utilizator deea101Andreea deea101 Data 28 octombrie 2014 19:19:12
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.09 kb
#include <fstream>
#define NMAX 100001
using namespace std;
ifstream f("arbint.in");
ofstream g("arbint.out");

int arb[5*NMAX],N,v[NMAX];

int best(int a, int b)
{
    if(a>b) return a;
    else return b;
}

void update(int nod, int st, int dr, int x, int val)
{
    if(st==dr) arb[nod]=val;
    else
    {
        int mij=(st+dr)/2;
        if(x<=mij) update(2*nod,st,mij,x,val);
        else update(2*nod+1,mij+1,dr,x,val);

        arb[nod]=best(arb[2*nod],arb[2*nod+1]);
    }
}

int query(int nod, int st, int dr, int a, int b)
{
    if(a<=st && dr<=b)
        return arb[nod];
    else
    {
        int maxim=0,mij;
        mij=(st+dr)/2;
        if(a<=mij) maxim=query(2*nod,st,mij,a,b);
        if(b>mij) maxim=best(maxim,query(2*nod+1,mij+1,dr,a,b));

        return maxim;
    }
}
int main()
{
    int M,i,q,x,y;
    f>>N>>M;

    for(i=1;i<=N;i++)
    {
        f>>v[i];
        update(1,1,N,i,v[i]);
    }


    while(M--)
    {
        f>>q>>x>>y;
        if(!q)
            g<<query(1,1,N,x,y)<<'\n';
        else update(1,1,N,x,y);
    }
}