212. Word Search II

Loading Question ...

Given a 2D board and a list of words from the dictionary, find all words in the board.

Each word must be constructed from letters of sequentially adjacent cell, where "adjacent" cells are those horizontally or vertically neighboring. The same letter cell may not be used more than once in a word.

For example,
Given words = ["oath","pea","eat","rain"] and board =

[
  ['o','a','a','n'],
  ['e','t','a','e'],
  ['i','h','k','r'],
  ['i','f','l','v']
]
Return ["eat","oath"].

Note:
You may assume that all inputs are consist of lowercase letters a-z.

click to show hint.

You would need to optimize your backtracking to pass the larger test. Could you stop backtracking earlier?

If the current candidate does not exist in all words' prefix, you could stop backtracking immediately. What kind of data structure could answer such query efficiently? Does a hash table work? Why or why not? How about a Trie? If you would like to learn how to implement a basic trie, please work on this problem: Implement Trie (Prefix Tree) first.


Seen this question in a real interview before?  
Yes
No
When did you encounter this question?  
last week
last month
last 3 month
last 6 month
more than 6 months
other
Which company?  
Adobe
Aetion
Airbnb
Alibaba
Amazon
Apple
Baidu
Bloomberg
Cloudera
Coursera
Cryptic Studios
Dropbox
eBay
Epic Systems
Expedia
Facebook
Fallible
Games
Gilt Groupe
GoDaddy
Goo
Google
Hedvig
Houzz
Hulu
Indeed
Intuit
IXL
LinkedIn
LiveRamp
Lyft
MAQ Software
Mathworks
Microsoft
NetEase
Netsuite
Palantir
Palantir Technologies
Pinterest
Pocket Gems
Poynt
Pure
Pure Storage
Rackspace
Riot
Riot Games
Samsung
Snapchat
Square
Storage
Tencent
TinyCo
Twitter
Two Sigma
Uber
Valve
WAP
Works Applications
Yahoo
Yahoo!
Yelp
Zappos
Zenefits