interview-prep | Data Structures / Algorithms for Coding Interviews | Dataset library
kandi X-RAY | interview-prep Summary
kandi X-RAY | interview-prep Summary
Here is how to prepare for Data Structures / Algorithms for Coding Interviews. This is a comprehensive collection of problems across hot interview topics like Dynamic Programming, LinkedLists, Greedy, Arrays, Binary Trees, Trees, etc.
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QUESTION
I've begun learning Go, and I ran into a strange bug, and an even stranger fix for it working on a HackerRack problem:
...ANSWER
Answered 2021-Jun-12 at 06:41So we have an actually correct answer here, the issue is that you're writing to the boolean but never reading from it. Without the Println()
, it's not used in a conditional or any other expression anywhere that depends on its value, so the assignments to it don't affect the program flow. You could remove all of the lines assigning values to insideValley
and the program would act no differently than it does right now (excepting the Println(), of course, which is why adding that "fixed" the issue).
Go is specifically designed to flag "junk" code like that, that adds nothing to the program flow, as a compiler error (well, in most cases. Unused globals and unused functions are some exceptions to that). Simply add in whatever is supposed to be using that boolean's value (such as a conditional based on its value), and you'll stop getting the "variable unused" error.
And as noted in the comments of Vishwa Ratna's answer, vars do not have to be used in every logical pathway. They only need to be used (ie. read from) in at least one logical pathway.
QUESTION
I'm doing this question on hackerrank: https://www.hackerrank.com/challenges/ctci-bubble-sort/problem?h_l=interview&playlist_slugs%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D=sorting
I wrote the solution in intellij, and it gives me the correct output there, but when I copied it over to the hackerrank ide, it gave me an error.
This is the code I'm talking about:
...ANSWER
Answered 2021-May-27 at 16:04You have put the Solution class within your Result class. HackerRank wants you to put the Solution class as its own class, like this:
QUESTION
I have the following solution:
...ANSWER
Answered 2021-May-21 at 11:54after testing this for about an hour or so, I realized where you're mistaken. Namely, using prn
instead of print
prints out the quote characters alongside the actual text. This was a surprise to me, since I always thought that these two are interchangeable. If you change your prn
s to println
s, you should be okay.
The final code that I created which passed all of the tests:
QUESTION
I am trying to practise a question on hackerrank. Problem link
I am trying to read the variable q
...ANSWER
Answered 2021-May-01 at 05:35Carefully consider the way the solution template is written, the function minimimumBribes is being called with two different test cases one after another, not as array of test cases. You would want to do some processing and print the solution for each case in new line.
As for deconstruction of arrays in javascript:
QUESTION
Given a numeric vector, I'd like to find the smallest absolute difference in combinations of size 2. However, the point of friction comes with the use of combn
to create the matrix holding the pairs. How would one handle issues when a matrix/vector is too large?
When the number of resulting pairs (number of columns) using combn
is too large, I get the following error:
Error in matrix(r, nrow = len.r, ncol = count) : invalid 'ncol' value (too large or NA)
This post states that the size limit of a matrix is roughly one billion rows and two columns.
Here is the code I've used. Apologies for the use of cat
in my function output -- I'm solving the Minimum Absolute Difference in an Array Greedy Algorithm problem in HackerRank and R outputs are only counted as correct if they're given using cat
:
ANSWER
Answered 2020-Nov-21 at 21:27Something like this?
QUESTION
Can someone explain what is wrong with my code? I am getting "Abort called" in 7 test cases. Rest are successful.
I have a 2d dp array with of size: n+1 x m+1 were n and m are sizes of a and b respectively. So, the row represent string a and columns represent string b.
First, I set dp[0][0] to 1 since it is possible to turn empty string into empty.
So, initially, i am checking if I can turn any substring of a into the empty string (in the first single for-loop). This is true for all substrings of a without any capital letters. As soon as there is a capital letter, the rest of the substrings cannot be converted.
Then (in the next double for-loop), I am examining all the cases.
Case 1: a[i-1] == b[i-1] -> if both the letter are the exact same, then dp[i][j] = dp[i-1][j-1]
Case 2: a[i-1] is lower case (this has 2 sub cases):
Case 2.1: a[i-1] and b[j-1] are the same letter (but not the same case) -> then we can either change a[i-1] or delete it . So:
dp[i][j] = dp[i-1][j-1] || dp[i-1][j].
Case 2.2: a[i-1] and b[j-1] are not the same -> in this case, we can only delete a[i-1] since it is lower case . So: dp[i][j] =
dp[i-1][j]
Link to problem: https://www.hackerrank.com/challenges/abbr/problem?h_l=interview&playlist_slugs%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D=dynamic-programming
P.S. The main logic of the program is just inside the abbreviation() function.
Code (EDITTED):
...ANSWER
Answered 2020-Nov-30 at 09:33The error in the code is "Segmentation fault".
Because of the following loop:
QUESTION
So I've been solving this HackerRank problem and I can't really see why my answer isn't working. I've now seen other people's answers and they make sense but it's a completely different approach and I really want to understand why mine doesn't work. It passes two test cases but not the third one. If you all think it's just mathematically or logically off and can explain why that would be awesome. Thanks!
This is the link to the question: https://www.hackerrank.com/challenges/new-year-chaos/problem?h_l=interview&playlist_slugs%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D=arrays
This is my code:
public class Solution {
...ANSWER
Answered 2020-Nov-25 at 14:34Your solution is wrong, because a change in position is not equivalent to a bribe. You can have bribes without a change in position and changes in position without a bribe. Start with 1 2 3 4 5
:
QUESTION
I am solving this hackerrank problem for counting the number of 'a'
s in a given string.
My solution was to store the string in a pattern
variable. While the length of the pattern
is less than n
, it will just add the string to itself. Then I would loop over the pattern
and add the number of 'a'
s in the string.
This solution works fine when n
< 1000000
. But add one more 0 and when n
= 10000000
, I get a RangeError
for my string in hackerrank because it's too damn long.
Is there a way to get around this RangeError
problem? I know there are other ways to solve this problem, but I just want to know how I could edit my code to make it pass the hackerrank test.
ANSWER
Answered 2020-Sep-24 at 04:17You could do math on this rather than consume the memory and calculation on string concatenation and loop
The total number of a
would be the number of a
in s
times the repeated number of s
that has total length not exceed n
, plus the remainder (left substring) of s
that fill the n
For example, with the input
QUESTION
We have a method in which an array and number of rotations are passed as input and we have to return the array after left rotations. Here is my solution.
...ANSWER
Answered 2020-Sep-09 at 14:51When you do the following:
QUESTION
Question Desc: Sherlock considers a string to be valid if all characters of the string appear the same number of times. It is also valid if he can remove just 1 character at 1 index in the string, and the remaining characters will occur the same number of times. Given a string s, determine if it is valid. If so, return YES, otherwise return NO.
...ANSWER
Answered 2020-Aug-21 at 13:26It's because of the initial values you've set for your variables. On the very first step of your iteration through temp
you'll find that ele == item
(because both are temp[0]
), and then subsequently that chk == True
(because you set it so). After the first step it'll print yes and break immediately.
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