aoc2021_day3_part1.js

(function(inp)
{
  let gbits = '';
  
  const width = 12;
  inp = inp.replaceAll('\n', '');
  let ones = [0,0,0,0,0,0,0,0,0,0,0,0];
  let zeros = [0,0,0,0,0,0,0,0,0,0,0,0];
  
  for(let index = 0; index < inp.length; index++)
  {
    let x = index % width;
    if(inp[index] == '1')
    {
      ones[x]++;
    }
    else
    {
      zeros[x]++;
    }
  }
  
  for(let i = 0; i < width; i++)
  {
    if(ones[i] > zeros[i])
    {
      gbits += '1';
    }
    else
    {
      gbits += '0';
    }
  }
  
  let gamma = parseInt(gbits, 2);
  
  let epsilon = gamma ^ 0b111111111111; 
  
  return epsilon * gamma;
})(document.querySelector('pre').innerHTML);