Cows and Bulls

by Steven Senkus

HTML

<pre id="output"></pre>

JavaScript

/**
You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the number is. Each time your friend makes a guess, you provide a hint that indicates how many digits in said guess match your secret number exactly in both digit and position (called "bulls") and how many digits match the secret number but locate in the wrong position (called "cows"). Your friend will use successive guesses and hints to eventually derive the secret number.

Write a function to return a hint according to the secret number and friend's guess, use A to indicate the bulls and B to indicate the cows. 

Please note that both secret number and friend's guess may contain duplicate digits.


*/

console.log = function() {
  const args = Array.from(arguments)
  const target = document.querySelector('#output');
  target.innerHTML = target.innerHTML + '\n' + args.join(' ')
}

let secret = '1807';


const getHint = function(secret, guess) {
  console.log(secret, guess)
  // short circuit if equal
  if (secret === guess) return `${guess.length}A0B`;

  secret = secret.split('');
  guess = guess.split('');

  let bullNum = 0;
  let cowNum = 0;

  // check for exact position and value matches, "bull"
  for (let i = 0; i < guess.length; i++) {
    if (guess[i] === secret[i]) {
      console.log('bull', i)
      bullNum++;
      secret[i] = 'X'
      guess[i] = 'X';
      continue;
    }
  }

  // check for value matches, "cow"
  upperloop:
    for (let j = 0; j < secret.length; j++) {
        if(guess[j] === 'K') continue;


      innerloop: for (let k = 0; k < secret.length; k++) {
        // already checked with bull run
        if (j === k) {
          console.log('already checked with bull run');
          continue;
        }

        
        if (secret[k] === 'X') {
          console.log('already used');
          continue;
        }
        console.log('j', j, 'k', k, '| guess:', guess[j], 'secret:', secret[k], 'secret: ',...