progetto-asd-2022/aux.cpp

#pragma once

#include <iostream>
#include <vector>
#include <unordered_set>
#include <unordered_map>
#include <algorithm>
#include <stdlib.h>
#include <time.h>

using namespace std;

/**
 * @brief Function that generates the next combination of k elements from a set of n elements
 */
bool nextComb(vector<int> &indices, int n) {
    int k = indices.size();
    int i = n - 1;
    int j = k - 1;
    while (indices[j] == i) {
        if (j == 0)
            return 1;
        i--;
        j--;
    }
    indices[j]++;
    for (int l = 0; l <= k - j - 1; l++) {
        indices[j + l] = indices[j] + l;
    }
    return 0;
}

/**
 * @brief Function that returns the intersection of two sets
 */
template <typename S>
unordered_set<S> intersectSets(unordered_set<S> s1, unordered_set<S> s2) {
    unordered_set<S> s;
    if (s1.size() <= s2.size()) {
        for (auto &el : s1) {
            if (s2.find(el) != s2.end()) {
                s.insert(el);
            }
        }
    }
    else {
        for (auto &el : s2) {
            if (s1.find(el) != s1.end()) {
                s.insert(el);
            }
        }
    }
    return s;
}

/**
 * @brief Function that shuffles the keys of a map and returns them in a vector
 * 
 * @param map: the map to shuffle
 * @param seed: the seed for the random number generator
 */
template <typename K, typename V>
vector<K> getShuffleKeys(unordered_map<K, V> map, long seed) {
    if (seed != -1)
        srand(seed);
    else
        srand(time(NULL));
    vector<K> output;
    for (auto& pair : map) {
        output.push_back(pair.first);
    }
    random_shuffle(output.begin(), output.end());
    return output;
}