Cod sursa(job #1970141)

Utilizator mariapascuMaria Pascu mariapascu Data 18 aprilie 2017 22:19:40
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.2 kb
#include <fstream>
using namespace std;

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

const int DIM = 100004;

int n, m;
int op, p, val, a, b, vmax;
int st[4 * DIM];

void Update(int x, int l, int r);
void Query(int x, int l, int r);

int main() {
    fin >> n >> m;
    for (int i = 1; i <= n; i++) {
        fin >> val;
        p = i;
        Update(1, 1, n);
    }
    for (int i = 1; i <= m; i++) {
        fin >> op >> a >> b;
        if (op == 0) {
            vmax = -1;
            Query(1, 1, n);
            fout << vmax << '\n';
        }
        else {
            p = a; val = b;
            Update(1, 1, n);
        }
    }
    fin.close();
    fout.close();
    return 0;
}

void Query(int x, int l, int r) {
    if (a <= l && r <= b) {
        vmax = max(vmax, st[x]);
        return;
    }
    int m = (l + r) / 2;
    if (a <= m) Query(2 * x, l, m);
    if (b > m) Query(2 * x + 1, m + 1, r);
}

void Update(int x, int l, int r) {
    if (l == r) {
        st[x] = val;
        return;
    }
    int m = (l + r) / 2;
    if (p <= m) Update(2 * x, l, m);
    else Update(2 * x + 1, m + 1, r);
    st[x] = max(st[2 * x], st[2 * x + 1]);
}