[Leetcode Solution] Word Ladder

GOOD PROBLEM

Analysis

• Breadth first search is used 
• when the end word is reached, the search finished and return the current search depth
• if the search queue has been empty and end word is till not reached, return 0 denote no transformation sequence
• erase the node from dict once it is reached because it is no more useful in the bfs

Note

• using a queue to implement the BFS
• implementation of bi-direction BFS
• implementation BFS how to erase the searching nodes while doing searching( queue.erase(iterator++)
• implementation BFS only needs to store two search level current and next which searches iteratively

Code

UPDATED AT LEETCODE 2ND PASS