Cod sursa(job #1812745)

Utilizator larecursividadLa Recursividad larecursividad Data 22 noiembrie 2016 12:51:03
Problema Arbori de intervale Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.72 kb
#include <fstream>
#define MAX 100001

using namespace std;

void query (unsigned int node, unsigned int left, unsigned int right);
void update (unsigned int node, unsigned int left, unsigned int right);

unsigned int N, M;
unsigned int X;
unsigned int a, b;

int maxArb[4*MAX+66];
unsigned int start, finish, pos, val;
int maximum;
unsigned int i, j;

int main ()
{
    ifstream fin ("arbint.in");
    ofstream fout ("arbint.out");
    fin >> N >> M;
    for (i=1; i<=N; i++)
    {
        fin >> X;
        pos = i;
        val = X;
        update(1,1,N);
    }
    for (i=1; i<=M; i++)
    {
        fin >> X >> a >> b;
        if (X == 0)
        {
            maximum = -1;
            start = a;
            finish = b;
            query(1,1,N);
            fout << maximum << '\n';
        }
        else
        {
            pos = a;
            val = b;
            update(1,1,N);
        }
    }
    fin.close();
    fout.close();
    return 0;
}

void query (unsigned int node, unsigned int left, unsigned int right)
{
    unsigned int mid;
    if (start<=left && right<=finish)
    {
        if (maximum < maxArb[node])
            maximum = maxArb[node];
        return;
    }
    mid = (left+right)/2;
    if (start <= mid)
        query(2*node,left,mid);
    else
        query(2*node+1,mid+1,right);
}

void update (unsigned int node, unsigned int left, unsigned int right)
{
    unsigned int mid;
    if (left == right)
    {
        maxArb[node] = val;
        return;
    }
    mid = (left+right)/2;
    if (pos <= mid)
        update(2*node,left,mid);
    else
        update(2*node+1,mid+1,right);
    maxArb[node] = max(maxArb[2*node],maxArb[2*node+1]);
}