Use Node.js to run edit-step-ladders.js with no arguments to process the default test file, basicdict.txt:
# node edit-step-ladders.js
Or, include a filename as an argument to process those words instead:
node edit-step-ladders.js unixdict.txt
This program identifies the number of words in the longest path of edit steps, as described below in the problem statement. It takes optional user input in the form of a filename for a dictionary, which is also described in the problem statement. After reading and processing either the default dictionary or a user-supplied file, a modified depth-first search algorithm is performed to pick the longest path.
Edit Step Ladders
An edit step is a transformation from one word X to another word Y such that X and Y are words in the dictionary, and X can be transformed to Y by adding, deleting, or changing one letter. The transformations from “dig" to “dog" and from “dog" to “do" are both edit steps. An edit step ladder is a lexicographically sorted set of words W1 , W2 , . . . , Wn such that the transformation from Wi to Wi+1 is an edit step for all i from 1 to n − 1.
For a given dictionary, you are to compute the length of the longest edit step ladder.
Input
The input to your program consists of the dictionary: a set of lowercase words sorted in lexicographic order at one word per line. No word exceeds 16 letters and there are at most 25,000 words in the dictionary.
Output
The output consists of a single integer, the number of words in the longest edit step ladder.
Sample Input
cat
dig
dog
fig
fin
fine
fog
log
wine
Expected Sample Output 5