Cod sursa(job #627108)

Utilizator igsifvevc avb igsi Data 29 octombrie 2011 00:11:18
Problema Arbori de intervale Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.39 kb
#include <fstream>
using namespace std;
#define maximN 100001
ifstream fin("arbint.in");
ofstream fout("arbint.out");

int arb[4*maximN], m, n, maxim;

void actualizare(int nod, int st, int dr, int poz, int val);
void interogare(int nod, int st, int dr, int a, int b);

int main(){
    fin >> n >> m;
    int op, a, b;

    for(int i = 1; i<=n; i++){
        fin >> a;
        actualizare(1, 1, n, i, a);
    }
    for(int i = 1; i<=m; i++){
        fin >> op >> a >> b;
        if(op == 0){
            maxim = 0;
            interogare(1, 1, n, a, b);
            fout << maxim << '\n';
        }
        else
            actualizare(1, 1, n, a, b);
    }
    fout.close();
    return 0;
}

void actualizare(int nod, int st, int dr, int poz, int val){
    if(st == dr)    {
        arb[nod] = val;
        return;
    }
    int mij = (st+dr)/2;
    if(poz <= mij)
        actualizare(2*nod, st, mij, poz, val);
    else
        actualizare(2*nod+1, mij+1, dr, poz, val);
    arb[nod] = (arb[2*nod] <= arb[2*nod+1] ? arb[2*nod+1] : arb[2*nod]);
}

void interogare(int nod, int st, int dr, int a, int b){
    if(a <= st && dr <= b)
        maxim = (maxim < arb[nod] ? arb[nod] : maxim);
    else{
        int mij = (st+dr) /2;
        if(a <= mij)
            interogare(2*nod, st, mij,a, b);
        if(mij < b)
            interogare(2*nod+1, mij+1, dr, a, b);
    }
}