职位是 SDE-II
在三番
Round 1: System Design
Design a system for dynamically assigning phone numbers to twilio customers
Round 2:
https://leetcode.com/problems/implement-queue-using-stacks/
Questions on multi-threaded queue design
Round 3:
Behavioral with previous project questions
Round4:
Given an array which contains 1-9 keys in a phone dial pad. To traverse this key pad you can only move either 1 step up/down/left/right first and then 3 steps agian in up/down/left/right direction or vice versa.
Find out the number of unique destinations you can reach with a path of length 4 starting from a source key. Additionaly this dial pad has one disabled key (x), so you cannot take that path.
Example:
Input: [1,2,3,4,x,6,7,8,9] , Source: 3
Output: 7
Explanation:
1 2 3
4 x 6
7 8 9
Source: 3
path1 : 3->6->9->8
path2: 3->2->1->4
When there are no more paths left to explore from 3 so we explore the paths from 8 and 4 where we reached by traversing through 3
path3: 8->7->4->1
path4: 4->7->8->9
Again repeating the same steps we explore paths from 1 and 9
path5: 1->2->3->6
path6: 9->6->3->2
Then with 6 as next source
path7: 6->9->8->7
Note: The paths we traverse may have the same nodes but the destinations must be unique.