Cod sursa(job #2029755)

Utilizator gabib97Gabriel Boroghina gabib97 Data 30 septembrie 2017 13:29:14
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.17 kb
#include <bits/stdc++.h>

#define N 100005
using namespace std;
int m, n, pos[N], v[N], A[270000];

void build(int k, int a, int b)
{
    if (a == b) pos[a] = k, A[k] = v[a];
    else
    {
        int m = (a + b) >> 1;
        build(k << 1, a, m);
        build((k << 1) + 1, m + 1, b);
        A[k] = max(A[k << 1], A[(k << 1) + 1]);
    }
}

int query(int k, int x, int y, int a, int b)
{
    if (a <= x && y <= b) return A[k];
    else
    {
        int q = 0, w = 0;
        int m = (x + y) >> 1;
        if (m >= a) q = query(k << 1, x, m, a, b);
        if (m < b) w = query((k << 1) + 1, m + 1, y, a, b);
        return max(q, w);
    }
}

void update(int k)
{
    A[k] = max(A[k << 1], A[(k << 1) + 1]);
    if (k)
        update(k >> 1);
}

int main()
{
    freopen("arbint.in", "r", stdin);
    freopen("arbint.out", "w", stdout);
    int i, a, b, t;
    scanf("%i%i", &n, &m);
    for (i = 1; i <= n; i++)
        scanf("%i", &v[i]);

    build(1, 1, n);
    while (m--)
    {
        scanf("%i%i%i", &t, &a, &b);

        if (!t) printf("%i\n", query(1, 1, n, a, b));
        else
        {
            A[pos[a]] = b;
            update(pos[a] >> 1);
        }
    }
    return 0;
}