const input = require('fs').readFileSync('d6.txt', 'utf8');

const solve = (input, mostCommon) => input.split('\n').reduce((res, line) => line.split('').reduce((res, c, index) => {
    let col = res[index] || {};
    col[c] = (col[c] || 0) + 1;
    res[index] = col;
    return res;
}, res), []).map(col => {
    let commonChar;
    for (let c in col) {
        if (!commonChar || (mostCommon && col[c] > col[commonChar]) ||
                (!mostCommon && col[c] < col[commonChar])) {
            commonChar = c;
        }
    }
    return commonChar;
}).join('');

console.log(`part1 answer: ${solve(input, true)}`);
console.log(`part2 answer: ${solve(input, false)}`);