How to Code The Merge Sort Algorithm in Java

[@aishikbhattacharya4296]

Best step by step explanation of merge sort code in KZbin

[@divyamehta2863]

initialization for right array can be resolved by taking ,int right[] = new int[array.length-mid]; Otherwise really a good explanation of code.

[@neolegionar]

True but first thing that came to my mind was int right[] = new int[mid+array.length%2]

[@phabove7]

@@neolegionar : It should be division and not modulo, right? Mod 2 will only return either 0 or 1.

[@DR-ng7oh]

I cannot even begin to say how much this helped

[@greentorainchannel386]

One of the best video in youtube for merge sort.. 👍👍👍👍👍 easy to understand and remember...

[@iamarnabpal]

This is the beauty of bottom-up approach. This tutorial is so easy to understand because Johnathon did a bottom-up approach. Hands down, the best tutorial on merge sort in Java on YT. This video should have had 1 million likes.

[@deepakmodi10]

No words to describe how easy you made this algo. Easy to understand.

[@markd2797]

2:46 this is ONE EXAMPLE of what made your tutorial different and exponentially better than other tutorials. You stopped and asked “what if” then proceeded to answer that “what if” immediately. Other tutorials just starts with an array of size 8, explains merge sort as “DiViDe aNd cOnqUeR” then call it a day. So, I’d like to say thank you for making this great tutorial.

[@rachamallidorasrivignesh4499]

The way of teaching is excellent johnathon tq.

[@xingjianwang1894]

This explanation is simpler and better than GeeksforGeeks, tbh.

[@saikiranj807]

Although I don't take paid courses online , I seriously think you should make one. You have a natural talent at explaining code. Seriously, it's the best explanation on KZbin, ever!

[@iyadshaheen4693]

just came across this, amazing video, I do have one comment and it just simplifies the code much more. my comment is that if the array of size 7 -> mid point is 7/2 = 3 you initialize that first array with size 3 and then you initialize the right array with, (consider array is the main original array name), array.length - midpoint size and that is 4 so that way you don't really need all those if else statements. it works if the array was of size 8 too (even split). other than that greatttt work and very good vid

[@javaexpertsa8947]

Unbelievable Tutorial, i tried so many courses and watched so many videos and still couldn't understand Merge Sort, because the instructor didn't explain the code well or just show the code without saying a single word. Thank you so much!

[@yolopassion]

The best explanation of Java Code for Merge Sort on You tube

[@nguyenphuc2046]

best explanation you could found on youtube

[@bm1078]

Thankyou so much, this explanation is literally so much better than what was in my textbook lol

[@cenkercanbulut3069]

Finally, someone, with full control over what he does , explaining it... A BIG THANKS LIKE AND SUB!

[@mongoose1618]

This is so much simpler to understand and easy to remember, Thank you! However, I think you must correct your IF condition at line 71 to if(left[leftPointer]

[@twitjunkie6007]

Are you talking about the case where elements in the left and right are same ? I tried creating an array with same elements and ran this code. It is working.

[@phabove7]

I think his code will also produce the same result. Because, without equality check, the first element in the right half should be the same.

[@HorizonSpeed26]

Thanks for the code explaination, now the implementation of merge sort makes sense in terms of the conceptual explaination of merge sort.

[@blastoice9281]

Gotta say, I like your solution the best. Clear explanation too, thanks alot.

[@DeepsWar]

This is such a great explanation. Had been struggling to understand the concept and code accordingly and this implementation & explanation is too good. Thanks again!

[@pradyumna668]

your explanation helped me a lot keep doing more videos on ds and algo

[@minhtanchu240]

Thank you so much! Easy to understand.

[@filiptomic8531]

Omg thank you so much this is the best explanation I found on KZbin

[@mikaelalvian8160]

Amazing explanation! Thank you, Sir!

[@laleen123]

By far the best version, Thank you

[@Morkizas]

The f***g BEST explanation of Merge Sort, you saved me a lot of nerves :)

[@romannejouta6546]

Very well explained!!! Thank you!

[@liyingfeng2464]

super clearly explained, thank you so much!

[@ramansb1008]

Excellent explaination!

[@yahiamostafa4718]

The Best Explanation

[@aneilievska9883]

OMG this was awesome, please when you have time cover Quick Sort.

[@rajshreerai628]

thank you.. this was awesome

[@vinayr2265]

wow.. excellent explanation.. the best one i came across.. thank you very much

[@hegyilevente221]

That one was life saving. Thank you!

[@davidaraujo2049]

Thank you soo soo much, you just saved my exam tomorrow !!!

[@maddy3656]

Very helpful, thank you!

[@rejithregi2588]

very clearly explained

[@Superb_virg]

Thank you great explanation. I have one question however: why does the incrementing of the pointers have to happen when they are used and not after? 18:05 And why do you get a weird output if you do not?

[@ankitjoshi6545]

Hey Samuel, It is not necessary to do leftpointer++. He just meant that do not forget to increment. you can split that (single line) result[resultpointer++] = left[leftpointer++]; is same as {three lines of code} result[resultpointer] = left[leftpointer]; resultpointer++; leftpointer++; you will get weird output if you do not increment . you will remain at the same pointer as previous iteration. you need to increment pointer to point next index in next iteration right.

[@rixflores4204]

Bro wtf you are the best 👌 thanks from mexico

[@mohdarshad9427]

best step by step code explaination ever found on youtube for merge sort thank u so much . how can i contact with u ?

[@palaksdarji]

This is superb.

[@Joy-mf6xo]

Thank you!

[@Mona001-01g]

Johnathon could you please also make a video for binary search in java. You explain so well. Somehow I understand much better when you do since i tried other videos in vain

[@ragabhassan1043]

that was great thank you

[@willemvheerden7185]

Awesome tutorial

[@zeeshanhasnani]

Thanks a lot! Your explanations were awesome and concise! :D

[@znveleisi1566]

what should i change to make it sort in a descending order

[@sivaprasath8766]

Awesome!!!!

[@SinteXCod]

Ty mate, now I finally understand it!

[@bouhenniouahiba8892]

i need help , how does the synchronization between several users (modify the same shared file) with algorithms

[@charlibravo2578]

Really helpful! Thank you so much!!

[@eoghanfeighery7383]

Just out of curiosity, is it possible to this program with an instantiable class containing multiple datatypes (String, integer, double)

[@luckypatilbhosle007]

I understood code .........Thank you sir...........

[@goodyramsesgarciatrujillan4035]

ur the best ty

[@sdfghuihef5602]

Thank you

[@606shann]

Awesome sir, Thanks a lot

[@FutureWiredTec]

Thank you very much that was very helpful

[@loisesp8061]

Where did you compile this? What app did you use to run this code. Thanks in advance :)

[@ramgopal2520]

I am somewhere stuck in the recursion of the method Merge. Could someone help me with it. Other than that I understood everything. And I have been going through merge sort for a lot of days and this guy nailed it with his explanation !! Still stuck in the recursive part 😢

[@kshitijnegi8151]

I am stuck too

[@Mona001-01g]

What happens when both leftpointer and righpointer values are equal?

[@muhammadahmadi7096]

Wow, was amazing 😍👌

[@irfancalsr7982]

Amazing

[@UKcouple173]

clearly explained thank you so much

[@adithyanalluri4881]

Excellent!!

[@vincemarkarnedo6644]

Great vid. But please next time add comments

[@tufanatha7798]

Awesome explanation ! few lines of coding can be reduced (27~35) by replacing: int[] right=new int[array.length-middle];

[@pointless8846]

Hey I really liek your video, I am pretty new to Java and I had a question about incrementing in your merge method, specifically about left[leftPointer++], wouldn't it increment first then chose the index. For example: leftPointer = 0 left[leftPointer++] would become left[1] or does in take leftPointer as the index then it increments? I am not sure if you understand my question.

[@-0----0----0----.-----.----.-7]

no it willl not....its postfix increment right...soo it willl only increment after....prefix which is ++x will do exactly as you said...but not postfix x++

[@pradyumna668]

thank you so much

[@drikast]

why did you increment: "result[rightPointer++] = right[rightPointer++]"? isn't it supposed to start from the first element [0]? Won't the increment point at the second[1]?

[@-0----0----0----.-----.----.-7]

no it willl not....its postfix increment right...soo it willl only increment after....prefix which is ++x will do exactly as you said...but not postfix x++

[@luckypatilbhosle007]

It is not working for large arrray.............. ArrayIndexOutOfBoundException is coming

[@waynemack6637]

does this with an odd amount of items in array

[@eagerassaultixopi4558]

at 2:08 i don't understand the usage if(array.length

[@GFC1337]

because if the array is of size 1, then it's [8] for example. Therefore it's already sorted. It's impossible for 1 number to be sorted.

[@qaipak1]

Correct me if wrong (and this might be nitpicking if I'm not) but around 12:00 when you are checking which one is less, should it not be less than equals to? Otherwise in equal cases the right and left will swap. Yes your array will be sorted but I believe Merge sort is supposed to be in place i.e, inputs should be in the order they were inserted in. Again I might be wrong being a novice.

[@JohnKwisses]

I believe that you are correct. The values will be the same, but for best practice, you should use

[@qaipak1]

@@JohnKwisses Thanks. Great video btw!

[@MYmotivationn]

perfect bro

[@jacobjacob5735]

Is this faster than comparing two numbers and switch their places within a counter for i and j?

[@arnoc.2107]

It is way more efficient. The runtime of a well-implemented mergeSort-algorithm is log(n) in the worst case. Meanwhile, having two for-loops comparing two elements at a time and switching them if necessary, has a WAY longer runtime.

[@manis8483]

Hi Johnathan Your way of explaining the code was just amazing. But when i try to recreate your code, i am getting an array out of bound exception. my code.... package sortingAlgo; public class MergeSorting { private static void printArray(int[] ar) { for (int i : ar) { System.out.print(i + " "); } System.out.println(); } private static int[] mergeSort(int[] ar) { if (ar.length

[@JohnKwisses]

Change this: for (int j = 0; j < right.length; j++) { right[j] = ar[midpoint + 1]; } To this: for (int j = 0; j < right.length; j++) { right[j] = ar[midpoint + j]; } In your mergeSort method (changing the 1 to a j).

[@vishalbisht5554]

The code explained by tutorial has error it will never work for larger array.

[@jm784952]

okkkkk. and i thought it was my mistake....how can i fix this?

[@curtistackie7459]

I don't understand what you mean by "while there are elements left in the array" at 17:37 when you don't delete any elements from any arrays at any point.

[@JohnKwisses]

The while loop will only run if there are elements still in the left or the right array starting from the left or right pointer position onwards. If a pointers position is equal to the length of its respective array, it means that there are no more elements to check in the array and the loop does not need to be run. For example, the loop would not run if the arrays did not contain any elements (the length of the array is not less than the position of its pointer). Another example, the loop would run if the left array had one element and the right array was empty (the length of the left array would be less than the position of its pointer). Same as if the right array had one element and the left array was empty (due to the exclusive OR operator as defined in the while loop). Hope this helps!

[@3bdoelnaggar]

THANKS

[@bantikumar8836]

too good !!!!! but these are easily understandable need clarity in graph and trees

[@samirallahverdi4948]

What a long soluthion!

[@AryanSingh2512.]

Why java code is so much different than C?

[@castro6612]

because they are different language

[@-0----0----0----.-----.----.-7]

me as a programmer duh.. 5:09

[@shadmansudipto7287]

at 8:30 you create pointers, but you do not explain what you mean by pointers, wastes a lot of time trying to understand that.

[@minhbui4817]

I love you. Plz have my baby