Improved cut the array problem #70

sergiolagunaswize · 2016-12-06T00:25:44Z

Problem statement has been changed, so it is clearer to the user

Also some List has been changed to ArrayList, so we have a list that has a natural sorting, because some list could have its own sorting and access implementation, causing a bigger complexity, or/and wrong output

Problem statement has been changed, so it is clearer to the user Also some List has been changed to ArrayList, so we have a list that has a natural sorting, because some list could have its own sorting and access implementation, causing a bigger complexity, or/and wrong output

zxul767

I like the new description better, less noise same core problem 👍

zxul767 · 2016-12-06T00:28:11Z

interview-process/engineers/questions/cutTheArray.md

@@ -3,15 +3,15 @@
 ## Interviewer Statement

 ```
-// A cut operation substracts the lowest element of the array from each number in that array.
+// A cut operation subtract the lowest element of the array from each positive number in that array.


The verb "subtract" was correctly conjugated, why did you change it?

what @zxul767 said. Also, if we say 'positive' we are giving the candidate more hints since the beginning IMHO.

@zxul767 I did not found the word substracts anywhere, and everywhere shows me a typo when I write that word; and I think the correct word was subtracts; I'll change to that word, unless we can demonstrate that substracts is a correct word
http://www.thefreedictionary.com/subtracts

I'm sorry, I meant the word "subtracts"

@jorgetinoco If we say: subtract the lowest element of the array from each number in that array the user might think that he only has to find the lowest element (that in the second operation is 0), and subtract that quantity to every elements of the array, causing that the program to never end (if the user makes the problem following that instruction); that's why I'm proposing to change it

@zxul767 Yes, the word subtracts is the one we have to use; I'll change it

Typo changed

zxul767 · 2016-12-06T00:33:11Z

interview-process/engineers/questions/cutTheArray.md

 // Example of cut operation:
 // array: [ 2,3,4,5,2 ]
 // lowest item: 2
 // array after cut operation: [ 0,1,2,3,0 ]
 // Problem:
 // You have an array or list of integer numbers greater than 0.
 // Write a function that performs a cut operation until all the elements of the array are 0.
-// The function must return the number of elements greater than 0 on each iteration
+// The function must print the number of elements greater than 0 on each iteration, or return a list(or array) with those numbers


I would suggest keeping the requirement of the problem to just return a list (they can always print it in the calling function if they want to visualize it for "debugging" purposes)

This has been changed to The function must return a list with the amount of elements greater than 0 on each iteration ; also the solution has been modified to match this problem description

zxul767 · 2016-12-06T00:33:57Z

interview-process/engineers/questions/cutTheArray.md

@@ -38,15 +38,15 @@ The elements greater than 0 are 4.

 Third iteration:
 The array after the cut operation is:
-`[ -1, 0, 1, -1, 0, 3 ]`
+`[ 0, 0, 1, 0, 0, 3 ]`


This certainly removes noise from the core problem 👍

There are different ways to solve this problem, one is to remove the numbers instead of substract everything, other is don't substract if it is already 0 and so on. So, in my opinion is better to leave it as a substraction works, but if everyone is good with this, go ahead

bobmazanec · 2016-12-06T02:33:56Z

I started adding this problem to our HackerRank library; how do you like this description?

jorgetinoco · 2016-12-06T16:28:31Z

interview-process/engineers/questions/cutTheArray.md

@@ -85,15 +85,15 @@ public void printIterations(List<Integer> nums) {

 ### Better solution O(n lg n)
 ```
-public void printIterations(List<Integer> nums) {
+public void printIterations(ArrayList<Integer> nums) {


Because of the principle implement to the interface is why I did it with List instead of ArrayList.

An interface give you the ability to specify a set of behaviors that all classes that implement the interface will share in common. Consequently, we can define variables and collections (such as arrays) that don't have to know in advance what kind of specific object they will hold, only that they'll hold objects that implement the interface.

Again, if everyone is good with this, go ahead.

I was thinking that maybe we get some implementation of list where the sort is not natural, so we can't get the numbers in ascending order when we iterate over them, causing that we don't get the correct solution at the end;
Or maybe, we get an implementation of list where the .get(index) operation costs O(n), causing this algorithm to be an O(n^2) solution

bobmazanec

Works for me!

zxul767 · 2016-12-07T17:24:11Z

@sergiolagunaswize thanks!

sergiolagunaswize assigned zxul767 Dec 6, 2016

zxul767 suggested changes Dec 6, 2016

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jorgetinoco reviewed Dec 6, 2016

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Resolved PR comments

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bobmazanec approved these changes Dec 7, 2016

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zxul767 approved these changes Dec 7, 2016

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sergiolagunaswize merged commit ad833b8 into master Dec 7, 2016

bobmazanec deleted the cut-the-array-problem branch March 31, 2017 16:36

vidalon unassigned zxul767 Feb 1, 2018

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Improved cut the array problem #70

Improved cut the array problem #70

sergiolagunaswize commented Dec 6, 2016

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zxul767 commented Dec 7, 2016

Improved cut the array problem #70

Improved cut the array problem #70

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zxul767 commented Dec 7, 2016

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