Cod sursa(job #2073996)

Utilizator stefan_creastaStefan Creasta stefan_creasta Data 23 noiembrie 2017 22:45:10
Problema Arbori de intervale Scor 30
Compilator cpp Status done
Runda Arhiva educationala Marime 1.45 kb
#include <cstdio>
#include <algorithm>
using namespace std;
const int NMAX = 100005;
int aint[4 * NMAX];
void update(int nod, int val, int poz, int st, int dr) {
    if(st > dr) {
        return ;
    }
    if(st == dr) {
        aint[nod] = val;
        return ;
    }
    int mij = (st + dr) / 2;
    if(mij >= poz) {
        update(2 * nod, val, poz, st, mij);
    }
    else {
        update(2 * nod + 1, val, poz, mij + 1, dr);
    }
    aint[nod] = max(aint[2 * nod], aint[2 * nod + 1]);
}
int query(int nod, int a, int b, int st, int dr) {
    if(dr < a) {
        return 0;
    }
    if(st > b) {
        return 0;
    }
    if(st == dr) {
        return aint[nod];
    }
    int sol = 0;
    int mij = (st + dr) / 2;
    if(st <= b) {
        sol = max(sol, query(2 * nod, a, b, st, mij));
    }
    if(dr >= a) {
        sol = max(sol, query(2 * nod + 1, a, b, mij + 1, dr));
    }
    return sol;
}

int main() {
    int n, m;
    freopen("arbint.in", "r", stdin);
    freopen("arbint.out", "w", stdout);
    scanf("%d%d", &n, &m);
    for(int i = 1; i <= n; ++i) {
        int x;
        scanf("%d", &x);
        update(1, x, i, 1, n);
    }
    for(int nrq = 0; nrq < m; ++nrq) {
        int op, a, b;
        scanf("%d%d%d", &op, &a, &b);
        if(op == 1) {
            update(1, b, a, 1, n);
        }
        else {
            printf("%d\n", query(1, a, b, 1, n));
        }
    }
    return 0;
}