Cod sursa(job #2858723)

Utilizator rares89_Dumitriu Rares rares89_ Data 28 februarie 2022 12:25:56
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.25 kb
#include <fstream>
#define INF 0x3f3f3f3f
 
using namespace std;
 
ifstream fin("arbint.in");
ofstream fout("arbint.out");
 
int n, q, c, x, y, maxTree[400005], poz, val;
 
void update(int nod, int st, int dr) {
    if(st == dr) {
        maxTree[nod] = val;
    } else {
        int mid = (st + dr) / 2;
        if(poz <= mid) {
            update(2 * nod, st, mid);
        } else {
            update(2 * nod + 1, mid + 1, dr);
        }
        maxTree[nod] = max(maxTree[2 * nod], maxTree[2 * nod + 1]);
    }
}

int query(int nod, int st, int dr, int x, int y) {
    if(st > y || dr < x) {
        return -INF;
    }
    if(st >= x && dr <= y) {
        return maxTree[nod];
    } else {
        int mid = (st + dr) / 2;
        return max(query(2 * nod, st, mid, x, y), query(2 * nod + 1, mid + 1, dr, x, y));
    }
}
 
int main() {
    fin >> n >> q;
    for(int i = 1; i <= n; i++) {
        fin >> x;
        poz = i, val = x;
        update(1, 1, n);
    }
    for(int i = 1; i <= q; i++) {
        fin >> c >> x >> y;
        if(c == 0) {
            fout << query(1, 1, n, x, y) << "\n";
        } else {
            poz = x, val = y;
            update(1, 1, n);
        }
    }
    fin.close();
    return 0;
}