Cod sursa(job #3041937)

Utilizator RobertCNMBrobertM RobertCNMB Data 2 aprilie 2023 21:22:14
Problema Arbori de intervale Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.64 kb
#include <fstream>

using namespace std;

ifstream cin("arbint.in");
ofstream cout("arbint.out");

const int NMAX = 1e5;

int n, a[NMAX + 1];
int Q;
int aint[4 * NMAX + 1];

void Build(int node, int left, int right)
{
    if(left == right)
        aint[node] = a[left];
    else
    {
        int mid = (left + right) / 2;
        Build(node * 2, left, mid);
        Build(node * 2 + 1, mid + 1, right);
        aint[node] = max(aint[node * 2], aint[node * 2 + 1]);
    }
}

void Update(int node, int left, int right, int pos, int value)
{
    if(left == right)
        aint[node] = value;
    else
    {
        int mid = (left + right) / 2;
        if(pos <= mid)
            Update(node * 2, left, mid, pos, value);
        else
            Update(node * 2 + 1, mid + 1, right, pos, value);

        aint[node] = max(aint[node * 2], aint[node * 2 + 1]);
    }
}

int Query(int node, int left, int right, int Qleft, int Qright)
{
    if(left >= Qleft && right <= Qright)
        return aint[node];

    int mid = (left + right) / 2;

    if(mid >= Qright)
        Query(node * 2, left, mid, Qleft, Qright);
    else if(mid + 1 <= Qleft)
        Query(node * 2 + 1, mid + 1, right, Qleft, Qright);

    int max1 = Query(node * 2, left, mid, Qleft, Qright);
    int max2 = Query(node * 2 + 1, mid + 1, right, Qleft, Qright);

    return max(max1, max2);
}

int main()
{
    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 == 1)
            Update(1, 1, n, x, y);
        else
            cout << Query(1, 1, n, x, y) << '\n';
    }


    return 0;
}