Cod sursa(job #1193376)

Utilizator rogoz.bogdanRogoz Bogdan rogoz.bogdan Data 31 mai 2014 16:41:26
Problema Arbori de intervale Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.47 kb
#include <cstdio>
#define MX 100001
using namespace std;

FILE *fin, *fout;

int n,m;
int a[4*MX];

int maxim(int i, int j)
{
    if(i > j) return i;
    return j;
}

void update(int nod, int left, int right, int poz, int x)
{
    if(left == right)
    {
        a[nod] = x;
        return;
    }

    int mid = (left+right)>>1;
    if(poz <= mid) update(nod<<1, left, mid, poz, x);
    else update((nod<<1)+1, mid+1, right, poz, x);

    a[nod] = maxim(a[nod<<1], a[(nod<<1)+1]);
}

int query(int nod, int left, int right, int i, int j)
{
    if(i<=left && right<=j) return a[nod];

    int mid = (left+right)>>1;
    int s,d;
    s=d=0;
    if(i <= mid)
    {
        s = query(nod<<1, left, mid, i, j);
    }

    if(mid < j)
    {
        d = query((nod<<1)+1, mid+1, right, i, j);
    }

    return maxim(s, d);
}

void citire()
{
    int i,x;
    fscanf(fin, "%d%d", &n, &m);
    for(i=1; i<=n; i++)
    {
        fscanf(fin, "%d", &x);
        update(1, 1, n, i, x);
    }
}

int main()
{
    int i,j,t,x,y,r;

    fin = fopen("arbint.in", "r");
    fout = fopen("arbint.out", "w");

    citire();
    for(i=1; i<=m; i++)
    {
        fscanf(fin, "%d%d%d", &t, &x, &y);
        if(t == 0)
        {
            r = query(1, 1, n, x, y);
            fprintf(fout, "%d%c", r, '\n');
        }
        else
        {
            update(1, 1, n, x, y);
        }
    }

    fclose(fin); fclose(fout);
    return 0;
}