DevFactorYT Hello Fellow HackerRanker's,
I created a video-tutorial walking through this problem and intend to walk through the rest of the problems (I am finished with most of DS on my main account).
Check out the walkthrough here: https://www.youtube.com/watch?v=hKQphShaM6g
Best Regards,
DevFactor
pablocrp_crm thx so much. i want to improve my programming skills
lochek_alon It seems like this solution is no longer working because the current program's structure seems more complex now than the one on your video. But anyway, thanks for the explanation and for the work you do.
pawanchoure910 ji sir
anshumansinghra2 [deleted]
dizmartin_gonza1 My c++ solution:
vector<int> reverseArray(vector<int> a) { int aux = 0; int n = a.size(); for (int i = 0; i < n/2; ++i) { aux = a[n-i-1]; a[n-i-1] = a[i]; a[i] = aux; } return a; }buzcuberk I'd say a much bettery solution (for c++14) is:
vector<int> reverseArray(vector<int> a) { vector<int> y; for(auto x = a.end()-1; x >= a.begin(); x--) y.push_back(*x); return y; }
i_eat_code not really a better solution. your solution requires a new y vector. so the space complexity is O(n), while the solution above did everything inplace, so its space complexity is O(1).
jjwcvca And I'd say much better is simply
vector<int> reverseArray(vector<int> a)
{
return {a.rbegin(), a.rend()};
}arpitpatel1771 just do this
reverse(a.begin(),a,end()); return a;
sathvikrijo why u typing this much.... i finished the code within a couple of lines in the function;
- reverse(a.begin(),a.en());
- return a;
that's all the finished...
buzcuberk the attempt was to show traversing backwards simply reverts it when you push back
sathvikrijo i cant understand you bro.
Kanahaiya You can follow the below link to know more.
Here is the video explaination - https://youtu.be/u_oUMtj7C3k
and you can find most of the hackerrank solutions with video explaination here- https://github.com/Java-aid/Hackerrank-Solutions
and many more needs to be addeed.
Regards,
Kanahaiya Gupta
Git Hub URL | https://github.com/Java-aid/
LIKE US | https://www.facebook.com/javaaid/
SUBSCRIBE US | https://www.youtube.com/channel/UCx1hbK753l3WhwXP5r93eYA
ravikumarmaliya return a[::-1]. this is much shorter ;p
clivic Can anyone explain why can't we just use the following plain approach compared to these solutions?
vector<int> reverseArray(vector<int> a) { vector<int> b; for(int i = a.size()-1;i>=0;i--){ b.push_back(a[i]); } return b; }
binarydevelop why -1 ???
t_j_jeffries_12 I don't think this is java but if its similar then maybe because the size method adds 1 to what the actual length is.
vashni_n_boamah the vector uses zero based indexing. therefore, you will be out of bounds if you access a.size();
Chandrabhan20071 cout<<"same here bro";
sean_novick That was my solution, except in Java.
dtrivedi I like this one. This is how would write up. The current programming structure looks really complex and it does not have to be this way. thanks for posting here so everyone knows. I am picking up programming after several years so atleast I can tell one way or other but newbies may not. thanks again
angiemarirodrig1 Can somebody please explain to me the aux variable and the whole swapping with a[n-i-1] = a[i];
This is so confusing to me.
roopeshkumaragra great you reduce it by aprox half
aimananjum15 my c solution: int* reverseArray(int a_count, int* a, int* result_count) { int b[a_count]; int j=a_count-1; *result_count=a_count; for(int i=0;i
sanjay_dev can anyone explain how is tis logic working as i am having trouble since n is fixed to 4. In for loop i<2 so i will start from 0 but effetive i in the loop for ++i will be 1 and 2 which the function swap a[1] to a[2] and do the same when i=2 so it is just reversing its impact. whereas when i run this solution and it has successfully completed all test case
shakti051 how did you write the comment my comment is shown in single line.
shakti051 How did you write the comment in well manner. My comment shown in single line.
macdhollister I'm getting a bug when trying to solve this with JavaScript. I didn't change any of the main method code, so everything from the error is pre-written.
solution.js:41 ws.write(res.join(' ') + '\n'); ^ TypeError: Cannot read property 'join' of undefined at main (solution.js:41:18) at ReadStream.<anonymous> (solution.js:20:5) at emitNone (events.js:111:20) at ReadStream.emit (events.js:208:7) at endReadableNT (_stream_readable.js:1064:12) at _combinedTickCallback (internal/process/next_tick.js:138:11) at process._tickCallback (internal/process/next_tick.js:180:9)
mkhoury87 I am getting the same error. Did you find out how to get around it?
edward_tirado I had this when I forgot to return the reversed array. Would need to see your code to help though.
evgeniy_aksyonov Same here =\
jchiguru Hey everyone, got this same error in Javascript.
Instead of console logging the reversedArray -- return it instead.
skurtov162 Exaclty. return a.reverse();
suprth Worked at last. Thanks.
ricardo_sibu the solution return a.reverse().join(' ');
I should have eliminated the join in the next line at main function ws.write(res.join(' ') + '\n');
satishbabuoffice Single line code in JavaScript
console.log(arr.reverse().join(' '));
pminkov Nice!
alxcherepanov Nice, it seems, you forgot another 28 lines of parsing.
That's what I call one line:
#!/usr/bin/env ruby gets && (puts gets.split.reverse.join(' '))
nyos22 2 lines in python, just because of n...
input() print(" ".join(str(x) for x in reversed(list(map(int, input().strip().split())))))
csixteen You can simplify your Python code:
input() print(" ".join(input().split(" ")[::-1]))
artgromov i think you forgot about number of digits to print (N)
csixteen Not necessary. I just take whatever comes as the second input, create a list from it, reverse it and print the elements glued with a space.
KeyurPotdar [deleted]msmsinghchauhan Your code didn't work.
>> print(input()==0 or " ".join(input().split()[::-1])) 10 20 30 40 50 50
a_kamal_89 I guess that you forgot to press Enter after the first integer input.
aliciali This works too.
n = int(input()) print(*list(input().split())[::-1])
shaurya2us What language is this? (Python or C++)
KeyurPotdar [deleted]
duy_tha304 Hello I'm new to python so could you please explain the * and [::-1] in the second line,please?
msmsinghchauhan - will unpack a list.
eg:
A=[1,2,3] print(*A) 1 2 3
we use [::] to slice. refer http://pythoncentral.io/how-to-slice-listsarrays-and-tuples-in-python/
eg: If we want to get a sliced list in reverse order.
print(A[::-1]) [3, 2, 1]
duy_tha304 Okay,got it.Thank you so much
- will unpack a list.
eg:
armyindiabts can u explain why u put * beforew list?
samaresh_yadav51 Is List is an Array? I think its not.
happyverma044 where is the value of n is used in the program? As it does not affect the number of inputs. like on custom inputs if n=0 then 7,8,9,3,5 will also executed properly.
sololobo [deleted]
srilusailaja10 for i in range(0,arr_count-1): return a[::-1] but this works better..
b_vsbrk abbo
lorentz_dll [deleted]
KeyurPotdar [deleted]an0o0nym one-liner
print(*[input().split() for _ in range(2)][1][::-1])
shaurya2us What language is this?
anirudhsingla8 python
vasanthmsvs can u xplain this plz..
jacky_xue_ds It doesn't work. No reponse output
jhrozo ## yet simplier, python has it all !! print(*arr[::-1])
rojastorrado The idea is make and understand what's happening behind scenes.. Make the algorithm.
jhrozo Ok, here is the explanation. The simple print(*arr[::-1]) is equivalent to:
output_str = "" inverse_array = arr[::-1] for element in inverse_array: output_str = output_str + " " + str(element) print(output_str)
This is why Python has it all.
dgaban lol. the challenge is to make the reverse algorithm yourself. you're still relying on just using arr[::-1] instead of actually writing that algorithm yourself.
nayak628 but it is still showing the same error before using this code Traceback (most recent call last): File "solution.py", line 31, in fptr.write(' '.join(map(str, res))) TypeError: 'NoneType' object is not iterable
sololobo In this case, return(a[::-1])
gurneeshchahal09 return a[::-1]
yuki_ Not as simple as yours, but how about this?
console.log(require('fs').readFileSync('/dev/stdin', 'utf8').split('\n')[1].split(' ').reverse().join(' '));
ltrico59 [deleted]
CSharpDev One-liner in C# too:
Console.WriteLine(string.Join(" ", arr.Reverse()));
aakashjaker1999 [deleted]marcantoinesegui hey this is my code below, but I still get wrong even tho when I lunch it on visual studio it work perfectly do you know why? for(int i =a.Length-1; i>=0; i--) {
Console.Write(a[i]+" "); } return a;
vasil_kolomiets really? do You like Python now?
def reverseArray(a):
return a[::-1]really 8 symbols...
prabaljainn Python is a way slower then C++ and Java, and at the end the user want speed with less space that's why we use c++ and java instead of python how muchh lines you wrote doesn't matter to the user.
afshan_shokath Gives me runtime error. Everything i write gives runtime error.
rodrigzer I did the same but it throws an error.
sdclarkie return a.reverse();
ryanbow923 fun reverse(a:Array)= a.apply{ a.reverse() }
karangale Simple Python Solution
def reverseArray(a): temp = [] size = len(a) for i in range(size-1, -1, -1): temp.append(a[i]) return temp
isahurrutia Similar idea in Python:
def reverseArray(a): rev = [] for i in range(len(a)): rev.append(a[len(a)-1-i]) return rev
:)
suryatejapatkari but the requried output should not be in the form of list
midhileshmomidi It will not be in the list because hackerrank is already doing from their side by this line (' '.join(map(str, res)))
183J1A0571 return a[::-1]
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