Cod sursa(job #1333233)

Utilizator radarobertRada Robert Gabriel radarobert Data 2 februarie 2015 22:06:37
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.52 kb
#include <cstdio>

using namespace std;

int arb[5000000];
int pos, val;

inline int max(int a, int b)
{
    if (a > b)
        return a;
    return b;
}

void update(int i, int left, int right)
{
    if (pos < left || pos > right)
        return;
    if (left == right)
    {
        arb[i] = val;
        return;
    }
    int mid = (left+right)/2;
    update(2*i, left, mid);
    update(2*i+1, mid+1, right);
    arb[i] = max(arb[2*i], arb[2*i+1]);
}

int q_left, q_right;
int vmax;

void query(int i, int left, int right)
{
    if (q_left <= left && right <= q_right)
    {
        vmax = max(arb[i], vmax);
        return;
    }
    int mid = (left+right)/2;
    if (q_left <= mid)
        query(2*i, left, mid);
    if (q_right > mid)
        query(2*i+1, mid+1, right);
}

int main()
{
    FILE *in = fopen("arbint.in", "r");
    FILE *out = fopen("arbint.out", "w");

    int n, m;
    fscanf(in, "%d%d", &n, &m);

    for (int x, i = 1; i <= n; ++i)
    {
        fscanf(in, "%d", &x);
        pos = i;
        val = x;
        update(1, 1, n);
    }

    int type, a, b;
    for (int i = 1; i <= m; ++i)
    {
        fscanf(in, "%d%d%d", &type, &a, &b);
        if (type == 0)
        {
            q_left = a;
            q_right = b;
            vmax = 0;
            query(1, 1, n);
            fprintf(out, "%d\n", vmax);
        }
        else
        {
            pos = a;
            val = b;
            update(1, 1, n);
        }
    }

    return 0;
}