Cod sursa(job #1858098)

Utilizator Dupree7FMI Ciobanu Andrei Dupree7 Data 27 ianuarie 2017 00:12:51
Problema Range minimum query Scor 80
Compilator cpp Status done
Runda Arhiva educationala Marime 1.43 kb
#include <fstream>

using namespace std;

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

int n, m, sgm_tree[400004], v[100001];

int minim(int a, int b)
{
    return (a > b) ? b : a;
}

void update(int node)
{
    sgm_tree[node] = minim(sgm_tree[node << 1], sgm_tree[(node << 1) + 1]);
}

void build_sgm_tree(int node, int left, int right)
{
    if(left == right)
        sgm_tree[node] = v[left];
    else
    {
        int mid = (right + left) >> 1;

        build_sgm_tree(node << 1, left, mid);
        build_sgm_tree((node << 1) + 1, mid + 1, right);

        update(node);
    }
}

int query(int node, int left, int right, int x, int y)
{
    if(x <= left && right <= y)
        return sgm_tree[node];
    else
    {
        int mid = (right + left) >> 1, answer = 0;

        if(x > mid)
            answer = minim(query((node << 1) + 1, mid + 1, right, x, y), 100001);
        else if(y <= mid)
            answer = minim(query(node << 1, left, mid, x, y), 100001);
        else
            answer = minim(query((node << 1) + 1, mid + 1, right, mid + 1, y), query(node << 1, left, mid, x, mid));

        return answer;
    }
}

int main()
{
    int i, a, b;

    f >> n >> m;

    for(i = 1; i < n + 1; i++)
        f >> v[i];

    build_sgm_tree(1, 1, n);

    for(i = 0; i < m; i++)
    {
        f >> a >> b;

        g << query(1, 1, n, a, b) << "\n";
    }

    return 0;
}