Cod sursa(job #1356825)

Utilizator costinbanuCostin Banu costinbanu Data 23 februarie 2015 16:52:52
Problema Range minimum query Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.05 kb
#include <fstream>
#include <algorithm>
using namespace std;

const int nmax = 100001, logmax = 18;

int A[nmax], D[nmax][logmax], N, Q, log2[nmax];

void build() {
    log2[1] = 0;
    for (int i = 2; i <= N; i++)
        log2[i] = log2[i / 2] + 1;
    for (int i = 0; i < N; i++)
        D[i][0] = i;
    for (int j = 1; (1 << j) <= N; j++)
        for (int i = 0; i + (1 << j) - 1 < N; i++)
            if (A[D[i][j - 1]] < A[D[i + (1 << (j - 1))][j - 1]]) D[i][j] = D[i][j - 1];
            else D[i][j] = D[i + (1 << (j - 1))][j - 1];
}
int query(int i, int j) {
    int k = log2[j - i + 1];
    if (A[D[i][k]] <= A[D[j - (1 << k) + 1][k]]) return D[i][k];
    else return D[j - (1 << k) + 1][k];
}

int main () {
    ifstream in ("rmq.in");
    ofstream out ("rmq.out");
    in >> N >> Q;
    for (int i = 0; i < N; i++)
        in >> A[i];
    build();
    int x, y;
    for (int i = 0; i < Q; i++) {
        in >> x >> y;
        out << A[query(x - 1, y - 1)] << endl;
    }
    in.close();
    out.close();
    return 0;
}