Cod sursa(job #2298761)

Utilizator ioana_marinescuMarinescu Ioana ioana_marinescu Data 8 decembrie 2018 14:19:22
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.78 kb
#include <fstream>
#include <assert.h>
const int MAX_N = 100000;

using namespace std;

ifstream fin("arbint.in");
ofstream fout("arbint.out");

int n, m;
int v[MAX_N + 5], arbint[1 << 18];

void build(int nod, int st, int dr) {
    if(st == dr)
        arbint[nod] = v[st];
    else {
        int mij = (st + dr) / 2;
        build(2 * nod, st, mij);
        build(2* nod + 1, mij + 1, dr);
        arbint[nod] = max(arbint[2 * nod], arbint[2 * nod + 1]);
    }
}

void update(int nod, int st, int dr, int index, int val) {
    assert((st <= index) && (index <= dr));

    if(st == dr)
        arbint[nod] = val;
    else {
        int mij = (st + dr) / 2;
        if(index <= mij)
            update(2 * nod, st, mij, index, val);
        else
            update(2 * nod + 1, mij + 1, dr, index, val);
        arbint[nod] = max(arbint[2 * nod], arbint[2 * nod + 1]);
    }
}

int query(int nod, int st, int dr, int left, int right) {
    assert((st <= left) && (left <= right) && (right <= dr));

    if((st == left) && (dr == right))
        return arbint[nod];
    else {
        int mij = (st + dr) / 2;
        if(right <= mij)
            return query(2 * nod, st, mij, left , right);
        else if (mij < left)
            return query(2 * nod + 1, mij + 1, dr, left, right);
        else
            return max(query(2 * nod, st , mij, left, mij), query(2 * nod + 1, mij + 1, dr, mij + 1, right));
    }
}

int main() {
    fin >> n >> m;

    for(int i = 1; i <= n; i++)
        fin >> v[i];

    build(1, 1, n);

    for(int i = 1; i <= m; i++) {
        int op, a, b;
        fin >> op >> a >> b;

        if(op == 0)
            fout << query(1, 1, n, a, b) << '\n';
        else
            update(1, 1, n, a, b);
    }
    return 0;
}