Algorithm Binary Agents - thelastmile/FreeCodeCamp GitHub Wiki

Algorithm Binary Agents

:triangular_flag_on_post: Remember to use Read-Search-Ask if you get stuck. Try to pair program :busts_in_silhouette: and write your own code :pencil:

Problem Explanation:

This problem is very straight forward, you will get a string that will represent a sentence in binary code, and you need to translate that into words. There is not direct way to do this so you will have to translate twice.

Relevant Links

:speech_balloon: Hint: 1

You should first convert from binary to decimal before translating those values into characters.

try to solve the problem now

:speech_balloon: Hint: 2

Things are easier when focusing on smaller parts, divide the input to focus on one letter at the time.

try to solve the problem now

:speech_balloon: Hint: 3

Make sure that each time you transcode a character from binary to decimal, you reset whatever variable you used to keep track of the ones. Also do not forget to turn everything back into one string.

try to solve the problem now

Spoiler Alert!

687474703a2f2f7777772e796f75726472756d2e636f6d2f796f75726472756d2f696d616765732f323030372f31302f31302f7265645f7761726e696e675f7369676e5f322e676966.gif

Solution ahead!

:beginner: Basic Code Solution:

function binaryAgent(str) {
  biString = str.split(' ');
  uniString = [];

/*using the radix (or base) parameter in parseInt, we can convert the binary
  number to a decimal number while simultaneously converting to a char*/

   for(i=0;i < biString.length;i++){
   uniString.push(String.fromCharCode(parseInt(biString[i], 2)));
  }
//we then simply join the string
  return uniString.join('');
}

// test here
binaryAgent("01000001 01110010 01100101 01101110 00100111 01110100 00100000 01100010 01101111 01101110 01100110 01101001 01110010 01100101 01110011 00100000 01100110 01110101 01101110 00100001 00111111");

:rocket: Run Code

Code Explanation:

  • Separate the string into an array of strings separated by whitespace.
  • Create some variables that will be needed along the way, the names are self explanatory for the most part.
  • Iterate through each binary string in the new array.
  • Convert to decimal by using parseInt(binary, 2) (with the second parameter we tell in which base our numbers currently are)
  • At the end, we return out converted message.

Relevant Links

:sunflower: Intermediate Code Solution:

function binaryAgent(str) {
  // Separate the binary code by space.
  str = str.split(' ');
  var power;
  var decValue = 0;
  var sentence = '';

  // Check each binary number from the array.
  for (var s = 0; s < str.length; s++) {
    // Check each bit from binary number
    for (var t = 0; t < str[s].length; t++) {
      // This only takes into consideration the active ones.
      if (str[s][t] == 1) {
        // This is quivalent to 2 ** position
        power = Math.pow(2, +str[s].length - t - 1);
        decValue += power;

        // Record the decimal value by adding the number to the previous one.
      }
    }

    // After the binary number is converted to decimal, convert it to string and store
    sentence += (String.fromCharCode(decValue));

    // Reset decimal value for next binary number.
    decValue = 0;
  }

  return sentence;
}

// test here
binaryAgent("01000001 01110010 01100101 01101110 00100111 01110100 00100000 01100010 01101111 01101110 01100110 01101001 01110010 01100101 01110011 00100000 01100110 01110101 01101110 00100001 00111111");

:rocket: Run Code

Code Explanation

  • For each of these binary strings, check for the ones and ignore the zeroes.
  • For those that are one or active then convert them to decimal, this takes into account the position and the right power it needs to be raised to.
  • Store the power into the power variable by adding it to any previous ones on the variable decValue. This variable will add and add the powers of the active ones until the end of the loop and then return the decimal number.
  • Convert the final decimal outside of the inner loop and then convert it to ASCII and saving it to sentence along with any other text string already converted and stored.
  • Reset the variable decValue to avoid getting wrong decimals before continuing to the outer loop.

Relevant Links

:rotating_light: Advanced Code Solution:

function binaryAgent(str) {
  return String.fromCharCode(...str.split(" ").map(function(char){ return parseInt(char, 2); }));
}

// test here
binaryAgent("01000001 01110010 01100101 01101110 00100111 01110100 00100000 01100010 01101111 01101110 01100110 01101001 01110010 01100101 01110011 00100000 01100110 01110101 01101110 00100001 00111111");

:rocket: Run Code

Code Explanation

  • First we use split() to be able to work on each character as an Array element
  • Then use map() to process each element from binary to decimal using pareseInt()
  • Last we can use String.fromCharCode() to convert each ASCII number into the corresponding character
  • However fromCharCode() expects a series of numbers rather than an Array! We can use ES6 Spread Operator to pass in an Array of numbers as individual numbers. See here for more info; Spread Operator

Relevant Links

:trophy: Credits:

If you found this page useful, you can give thanks by copying and pasting this on the main chat:

Thanks @Rafase282 @JamesKee @sabahang @crisvdkooij for your help with Algorithm: Binary Agents

:clipboard: NOTES FOR CONTRIBUTIONS:

  • :warning: DO NOT add solutions that are similar to any existing solutions. If you think it is similar but better, then try to merge (or replace) the existing similar solution.
  • Add an explanation of your solution.
  • Categorize the solution in one of the following categories — Basic, Intermediate and Advanced. :traffic_light:
  • Please add your username only if you have added any relevant main contents. (:warning: DO NOT remove any existing usernames)

See :point_right: Wiki Challenge Solution Template for reference.