Word Ladder - Whiteboarding exercise - HR RPT21

word-ladder-whiteboarding-exercise

// Whiteboard exercise: Word Ladder: https://leetcode.com/problems/word-ladder/description/

// NOTE: Interviewer did not progress into asking me for actual code, even though I actually 
finished pseudocode halfway through my sesion. Therefore I'm selecting the 'finished core concepts'
option in Google forms.


// Input:
// beginWord = "hit",
// endWord = "cog",
// wordList = ["hot","dot","dog","lot","log","cog"]

// Output: 5

// Input:
// beginWord = "hit"
// endWord = "cog"
// wordList = ["hot","dot","dog","lot","log"]

// Output: 0

// Explanation: The endWord "cog" is not in wordList, therefore no possible transformation.

// Input: beginWord, endWord, wordList (array of strings)
// Output: shortest transformation count from beginning to end
// Constraints: each word aside from beginWord must be in the wordList, 
//              all words same length, lowercase a-z letters, assume that words in wordList are same as begin/endWord
// Edge cases: endWord is not in wordList, empty wordList


// Example
// Input:
// beginWord = "hit",
// endWord = "cog",
// wordList = ["hot","dot","dog","lot","log","cog"]

// hit -> hot -> dot -> dog -> cog
// hit: hot // remove hot
// hot: dot, lot // remove dot, lot

// dot: dog // remove dog
// dog: cog // return count

// lot: log // remove log

// Output: 5


// Helper function:
// findNextWords: word, wordList -> subList of words that are one character off

// Initialize a list of possible nextWords

// For each letter in word 
  // For each word in wordList
  // If word has same letter in the same spot as our word
    // If one other character has the same letter as our word, add this word in wordList to nextWords

// Return nextWords


// Main function:
// if endWord not in wordList, return 0

// Initialize a counter
// Initialize an array of transformation counts
  // Recursive function: curWord, curWordList, counter
  // if curWord is endWord, add counter to array
  // findNextWords(curWord, curWordList) -> subList

  // Remove curWord and all words in subList from curWordList

  // For each of the words in the subList
    // Call recursive function with (word, copy of curWordList, incremented counter)
  

  // Call recursive function with initial args (beginWord, copy of wordList, initial counter)
// Return the minimum from array of transformation counts, or 0 if array is empty