Word Ladder (Shortest Path) in Java: Explanation & Practice

Find shortest transformation sequence

Problem summary

Given beginWord, endWord, and a dictionary, find the length of shortest transformation sequence. Each step changes one letter to form a word in the dictionary.

Starter code

public class Main {
    public static void main(String[] args) {
        String beginWord = "hit";
        String endWord = "cog";
        String[] wordList = {"hot","dot","dog","lot","log","cog"};
        
        // BFS from beginWord
        // Generate all possible one-letter changes
        // Check if in dictionary
        // Print: Length: 5
    }
}

Expected output and test cases

hit→hot→dot→dog→cog
```
Length: 5
```
endWord not in list
```
Length: 0
```
Direct transformation possible
```
Length: 2
```

Hints

BFS gives shortest path in unweighted graph
Each word is a node, edges connect words differing by one letter
Use HashSet for O(1) dictionary lookup
Remove words from set once visited to avoid cycles

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