Cod sursa(job #3204747)

Utilizator marius135Dumitran Adrian Marius marius135 Data 17 februarie 2024 13:06:02
Problema Range minimum query Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.39 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <cmath> // Added this line

using namespace std;

int get_min(vector<int> &array, int start, int end) {
  return *min_element(array.begin() + start, array.begin() + end + 1);
}

void build_sparse_table(vector<int> &array, vector<vector<int>> &sparse_table, int n) {
  for (int i = 0; i < n; i++) {
    sparse_table[i][0] = array[i];
  }

  for (int j = 1; (1 << j) <= n; j++) {
    for (int i = 0; i + (1 << j) <= n; i++) {
      sparse_table[i][j] = min(sparse_table[i][j - 1], sparse_table[i + (1 << (j - 1))][j - 1]);
    }
  }
}

int query(vector<vector<int>> &sparse_table, int n, int x, int y) {
  int k = (int)floor(log2(y - x + 1));
  return min(sparse_table[x][k], sparse_table[y - (1 << k) + 1][k]);
}

int main() {
  ifstream in("rmq.in");
  ofstream out("rmq.out");

  int n, m;
  in >> n >> m;

  vector<int> array(n);
  for (int i = 0; i < n; i++) {
    in >> array[i];
  }

  // Preprocess: Build sparse table
  int log_n = (int)floor(log2(n));
  vector<vector<int>> sparse_table(n, vector<int>(log_n + 1));
  build_sparse_table(array, sparse_table, n);

  // Answer queries
  for (int i = 0; i < m; i++) {
    int x, y;
    in >> x >> y;
    x--; // Adjust for 0-based indexing
    y--;

    int min_value = query(sparse_table, n, x, y);
    out << min_value << endl;
  }

  in.close();
  out.close();

  return 0;
}