AoC22/d02.cc

#include <iostream>
#include <vector>
#include <array>

using namespace std;

vector<array<unsigned, 2>> parse()
{
    vector<array<unsigned, 2>> input;
    string line;
    while (getline(cin, line)) {
        if (line.size() < 3 || line[1] != ' ') abort();
        unsigned oppo = line[0] - 'A';
        unsigned user = line[2] - 'X';
        if (oppo >= 3 || user >= 3) abort();
        input.push_back({oppo, user});
    }
    return input;
}

unsigned p1(vector<array<unsigned, 2>> &input)
{
    unsigned score = 0;
    for (array<unsigned, 2> i : input) {
        unsigned shape = i[1];
        unsigned outcome = (i[1] - i[0] + 4) % 3;
        score += shape + 1 + outcome * 3;
    }
    return score;
}

unsigned p2(vector<array<unsigned, 2>> &input)
{
    unsigned score = 0;
    for (array<unsigned, 2> i : input) {
        unsigned shape = (i[1] + i[0] + 2) % 3;
        unsigned outcome = i[1];
        score += shape + 1 + outcome * 3;
    }
    return score;
}

int main()
{
    auto input = parse();
    cout << p1(input) << endl;
    cout << p2(input) << endl;
}