Cod sursa(job #3305997)

Utilizator adimiclaus15Miclaus Adrian Stefan adimiclaus15 Data 6 august 2025 14:41:06
Problema Arbori de intervale Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.55 kb
#include <bits/stdc++.h>
using namespace std;

const int NMAX = 1e5;
int a[NMAX + 1], aint[4 * NMAX + 1];
int sol;

void build(int node, int st, int dr) {
    if(st == dr) {
        aint[node] = a[st];
    } else {
        int mid = (st + dr) / 2;
        build(2 * node, st, mid);
        build(2 * node + 1, mid + 1, dr);
        aint[node] = max(aint[2 * node], aint[2 * node + 1]);
    }
}

void update_pos(int node, int st, int dr, int pos, int val) {
    if(st == dr) {
        aint[node] = val;
    } else {
        int mid = (st + dr) / 2;
        if(pos <= mid) {
            update_pos(2 * node, st, mid, pos, val);
        } else {
            update_pos(2 * node + 1, mid + 1, dr, pos, val);
        }
        aint[node] = max(aint[2 * node], aint[2 * node + 1]);
    }
}

void query(int node, int st, int dr, int L, int R) {
    if(L <= st && dr <= R) {
        sol = max(sol, aint[node]);
    } else {
        int mid = (st + dr) / 2;
        if(L <= mid) {
            query(2 * node, st, mid, L, R);
        }
        if(mid + 1 <= R) {
            query(2 * node + 1, mid + 1, dr, L, R);
        }
    }
}


int main() {
    ifstream cin("arbint.in");
    ofstream cout("arbint.out");
    int n, q;
    cin >> n >> q;
    for(int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    build(1, 1, n);
    while(q--) {
        int tip, x, y;
        cin >> tip >> x >> y;
        if(tip == 0) {
            sol = 0;
            query(1, 1, n, x, y);
            cout << sol << '\n';
        } else {
            update_pos(1, 1, n, x, y);
        }
    }
    return 0;
}