Phone interview question # 1: Given an array (for example, [ 1, 0, 2, 0, 0, 3, 4 ]), implement methods that 1. returns the number of non-zero elements (4) 2. moves the non-zero elements to the beginning of the array (the rest of the elements don't matter) -> both [ 1, 2, 3, 4, 0, 0, 0] and [ 4, 1, 3, 2, X, Y, Z ] are valid
Verify that a binary search tree is indeed a binary search tree.
given an array of words, how to eliminate the duplicates? You have a simple tree structure Ⓐ and its clone ⓐ. Each node in the tree has a pointer to it's parent as well as an array of its children. Given an original tree's node Ⓑ and cloned tree ⓐ, implement a method that returns ⓑ (the clone of Ⓑ). (Imagine finding the matching UIButton/UISlider/UIView in a separate cloned view controller.) Original Ⓐ ┏━┻━━┓ ◯ ◯ ┏┻┓ ┏━╋━┓ ◯ ◯ ◯ ◯ ◯ ┏┻┓ ┃ ◯ Ⓑ ◯ Clone ⓐ ┏━┻━━┓ ◯ ◯ ┏┻┓ ┏━╋━┓ ◯ ◯ ◯ ◯ ◯ ┏┻┓ ┃ ◯ ⓑ ◯
Given nested arrays, write an enumerator class such that next() returns the elements in sequential order, e.g.: [1,[4,3],6,[5,[1,0]]] -> 1, 4, 3, 6, 5, 1, 0 also implement allObjects for this class
Take in an Int array and move all the zeroes to the end in place. It doesn’t matter how the non-zero numbers are ordered. Preferably as efficient and as space efficient as possible. Example: Input : [ 3, 0, 2, 0, 0, 4, 1, 0 ] Accepted Output: [ 4, 2, 3, 1, 0, 0, 0, 0 ]
If you have a program that runs slow, how will you improve it to run faster?
iOS developers have a "dispatch_after(when, queue, block)" Grand Central Dispatch (GCD) function they can utilize but once it's set up, these calls can not be easily cancelled. Describe how you might implement a more convenient version of this named "cancellable_dispatch_after"
One question 3 of the interviewers asked me was "What was the most difficult thing you had to deal with.".
They asked a lot of iOS questions, and some general programming questions. The first question they asked was so obscure that I didn't even really understand it. I was probably dead from that point on. Another question was to figure out a way to combine three lists of items where an item would be placed in a destination array if it existed in any two of the source arrays.
Can write a function which inputs two ints and check if it is 3 it should return 6 if input is 6 return 3, without using any condition.
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