Cod sursa(job #1499098)

Utilizator Vele_GeorgeVele George Vele_George Data 10 octombrie 2015 10:10:20
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.39 kb
#include <iostream>
#include <fstream>
#define nmax 100003
#define inf (1<<30) // 1*(2^30)
using namespace std;

ifstream f("arbint.in");
ofstream g("arbint.out");

int A[nmax], T[4*nmax], mx;

void update_arbint(int i, int st, int dr, int poz, int val)
{
    if (st == dr) T[i] = val;
    else
    {
        int mid = (st+dr)/2;
        if (poz <= mid) update_arbint(2*i, st, mid, poz, val);
                    else update_arbint(2*i+1, mid+1, dr, poz, val);
        T[i] = max(T[2*i], T[2*i+1]);
    }

    return;
}

void search_arbint(int i, int st, int dr, int a, int b)
{
    if(a <= st && dr <= b) mx=max(T[i], mx);
    else
    {
        int mid =(st+dr)/2;
        if( a <= mid ) search_arbint(2*i, st, mid, a, b);
        if( b > mid ) search_arbint(2*i+1, mid+1, dr, a, b);
    }

    return;
}

int main()
{
    int n, m;
    f >> n >>m;
    for(int i=1; i<=n; i++)
    {
        f >>A[i];
    }
    for(int i=1; i<=4*nmax; i++)
    {
        T[i]=0;
    }
    for(int i=1; i<=n; i++)
    {
        update_arbint(1, 1, n, i, A[i]);
    }
    int act, x, y;
    for(int i=1; i<=m; i++)
    {
        f >> act >> x >> y;
        if (act == 0)
        {
            mx = -inf;
            search_arbint(1, 1, n, x, y);
            g << mx << "\n";
        }
        else{
            update_arbint(1, 1, n, x, y);
        }
    }
    return 0;
}