Discussion on: AoC Day 2: Inventory Management System

[Anderson. J]

Javascript lazy solution
I don't have much time to solve the challenges :( So I'm just trying to get the stars.

part 1

let twoAppears = 0;
let threeAppears = 0;

for(ID of input) {
  const letters = new Set(ID.split(''));
  let twoAppearing = false;
  let threeAppearing = false;

  for(letter of letters) {
    const length = ID.match(new RegExp(letter, 'g')).length;

    switch (length) {
      case 2:
        if(!twoAppearing) {
          twoAppears++;
          twoAppearing = true;
        }
        break;
      case 3:
      if(!threeAppearing) {
        threeAppears++;
        threeAppearing = true;
      }
      break;
    }
  }
}

console.log(twoAppears * threeAppears);

Part 2

function getCommonLetters(string1, string2) {
  let commonLetters = [];

  for(let i=0; i<string1.length; i++) {
    if(string1[i] === string2[i] && string1[i] !== '\r') {
      commonLetters.push(string1[i]);
    }
  }
  return commonLetters;
}

let mostOcurrencies = [0, 0];
for(let i=0; i<input.length; i+=1) {
  for(let j=i+1; j<input.length; j+=1) {
    commonLetters = getCommonLetters(input[i], input[j]);
    if(commonLetters.length >= 1 && commonLetters.length > mostOcurrencies[0]) {
      mostOcurrencies[0] = commonLetters.length;
      mostOcurrencies[1] = commonLetters;
    }
  }
}

console.log(mostOcurrencies[1].join().replace(/,/g,''))