Cod sursa(job #1226280)

Utilizator pulseOvidiu Giorgi pulse Data 4 septembrie 2014 23:36:33
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.4 kb
#include <cstdio>
#include <algorithm>

using namespace std;

const int MAXN = 100005;
int N, M, Arb[3 * MAXN], pos, val, maxim, start, finish;

void Update(int node, int l, int r)
{
    if (l == r)
    {
        Arb[node] = val;
        return;
    }
    int mid = (l + r) / 2;
    if (pos <= mid)
        Update(2 * node, l, mid);
    else
        Update(2 * node + 1, mid + 1, r);
    Arb[node] = max(Arb[2 * node], Arb[2 * node + 1]);
}

void Query(int node, int l, int r)
{
    if (start <= l && r <= finish)
    {
        maxim = max(maxim, Arb[node]);
        return;
    }
    int mid = (l + r) / 2;
    if (start <= mid)
        Query(2 * node, l, mid);
    if (mid < finish)
        Query(2 * node + 1, mid + 1, r);
}

int main()
{
    freopen("arbint.in", "r", stdin);
    freopen("arbint.out", "w", stdout);
    scanf("%d %d", &N, &M);
    for (int i = 1, x; i <= N; ++i)
    {
        scanf("%d", &x);
        pos = i;
        val = x;
        Update(1, 1, N);
    }
    for (int type, a, b; M; --M)
    {
        scanf("%d %d %d", &type, &a, &b);
        if (type == 1)
        {
            pos = a;
            val = b;
            Update(1, 1, N);
        }
        else
        {
            start = a;
            finish = b;
            maxim = -1;
            Query(1, 1, N);
            printf("%d\n", maxim);
        }
    }
    return 0;
}