code: function getBit(arr, n) {
                  var index = n >> 5; // Same as Math.floor(n/32)
                  var mask = 1 << (31 - n % 32);
                  return Boolean(arr[index] & mask);
              }
docs: Gets the n value of array arr
  @param {Array} arr
  @param {number} n
  @return {boolean}