Risk Card Set Kata

riskSet.cpp

#include <algorithm>
#include <cassert>
#include <vector>
//#include <set>

using namespace std;
using card_t=char;
const card_t Jocker = 'J';

// Check if vector contains element
template <typename T>
bool contains(const vector<T> &hand, T card) {
    return find(hand.begin(), hand.end(), card) != hand.end();
}

// Get vector cardinality
template <typename T>
auto getCardinality(vector<T> hand) {
    // set<T> set(begin(hand), end(hand));
    sort(hand.begin(), hand.end());
    hand.erase(unique(hand.begin(), hand.end()), hand.end());
    return hand.size();
}

// Is equal distribution ?
bool eqDistr(const vector<card_t> &hand) {
    assert(hand.size() == 4);
    // is it X-X-Y-Y or X-Y-Y-Y ?
    auto cnt = count_if(hand.begin(), hand.end(), [&](char c) { return c == hand[0]; });
    return cnt == 2;
}

auto isValid(const vector<card_t> &hand) {
    if (hand.size() < 3) return false;
    if (hand.size() > 4) return true;
    if (contains(hand, Jocker)) return true; // 3 cards. Did vector contains 'J' ?
    if ((hand.size() == 4) && (!eqDistr(hand))) return true;

    auto crd = getCardinality(hand);
    if (crd >= 3) return true; // different cards
    if (crd == 1) return true; // all cards the same
    return false;              // X-Y-Y, no jocker case
}

auto main() -> int {
    // Invalid: less cards
    assert(!isValid({}));
    assert(!isValid({'C', 'C'}));

    // Valid: different cards
    assert(isValid({'C', 'S', 'H'}));
    assert(isValid({'C', 'H', 'J'}));
    assert(isValid({'C', 'S', 'H', 'J'}));

    // Valid: same cards
    assert(isValid({'C', 'C', 'C'}));
    assert(isValid({'J', 'J', 'J'}));

    // Use of 'J'
    assert(isValid({'S', 'S', 'J'}));
    assert(isValid({'S', 'J', 'S'}));
    assert(!isValid({'S', 'S', 'C'}));

    assert(isValid({'S', 'J', 'J'}));
    assert(isValid({'S', 'H', 'J'}));

    // Invalid cases
    assert(!isValid({'S', 'C', 'C'}));

    // 4 cards
    assert(isValid({'H', 'H', 'C', 'H'}));
    assert(isValid({'H', 'H', 'J', 'H'}));
    assert(isValid({'J', 'H', 'J', 'H'}));
    assert(!isValid({'H', 'H', 'C', 'C'}));

    // 5 cards
    assert(isValid({'H', 'H', 'C', 'H', 'C'}));
    assert(isValid({'H', 'H', 'C', 'H', 'H'}));

    return 0;
}