*DALIY CHALLENGE* : Given a positive int n. Generate a random int array of size n and count the inverses!

Question

INFO:
an inverse is an integer pair (left,right) where the left value is larger than the right value.

TASK:
1) generate random int array
2) calculate inverses

EXAMPLE: (n = 6)
a random array could be: [1,3,4,2,0,9]
- 1,0 is an inverse
- 3,2 is an inverse
- 3,0 is an inverse
- 4,2 is an inverse
- 4,0 is an inverse
- 2,0 is an inverse
---> this array has 6 inverses!

try to do this as EFFICIENT as possible !

HINT:
divide & conquer
(it's 2 faster as normal)

https://code.sololearn.com/cL0bV3ZFuN3j/?ref=app

Answer 1

This is my try, is there things I could improve ?
https://code.sololearn.com/c9j94Ken381p/?ref=app

Answer 2

My try:
https://code.sololearn.com/WW1cL9x40l4M/?ref=app

Answer 3

is this correct?

https://code.sololearn.com/c2674XRvnZcV/?ref=app

Answer 4

here mine: https://code.sololearn.com/WX4DVo4aIjnq/

example's one has 6 inverses instead :)

Answer 5

ALL YOUR ALGORITHMS ARE CORRECT BUT RUNNING IN O(n^2) RUNTIME ... TRY TO SPEED THEM UP ;)

Answer 6

I did some optimizations, there are probably some more. But good enough for me ^^

Without output it can handle up to around 500.000 on sololearn before reaching the memory limit.
*
Edit: with some more optimizations sololearn should be able to handle up to around 9.000.000 elements before reaching the time limit.
*

On my pc it can calculate an array of 100.000.000 elements within 5 seconds.

https://code.sololearn.com/ccVZvJB0vB25/?ref=app

Btw, in your example I think you're missing (2,0)

Answer 7

this is my Solution.

p.s. i did it hours ago, but put it in wrong challenge discussion
https://code.sololearn.com/c7PjGjS3QH34/?ref=app

Answer 8

My solution (C++)
:P
https://code.sololearn.com/c634WbQw0h2p/?ref=app

Answer 9

Here you go. Checks for valid numerical input.
https://code.sololearn.com/cvzXba4GLWjO/?ref=app

Answer 10

here my advertisement for: https://www.sololearn.com/Discuss/635638/?ref=app

sponsored by @Julian Fechner

Answer 11

my try (maybe, the simplest of all :p)
https://code.sololearn.com/c16Rop2pDtO0/?ref=app

Answer 12

https://code.sololearn.com/cK3b113TAmoj/#py

Answer 13

here is mine

give 2 inputs...
1) how many random elements in the array.
2)max limit for the random integer.

input eg: 6
189
( SEPERATED BY ENTER)
**it means 6 random integers between 0 to 189**

check it out..

https://code.sololearn.com/cE5DY9cX0CSh/?ref=app

Answer 14

My try

https://code.sololearn.com/cRKUlh6VM5aj/?ref=app

Answer 15

my limit for random integer is 9 not sure if this is correct.

https://code.sololearn.com/cjYmpiqPi6u3/?ref=app

Answer 16

Here is my try
https://code.sololearn.com/cnKzT5iZs16m/?ref=app

Answer 17

is it correct?
https://code.sololearn.com/cfqfMTfVxLED/?ref=app

Answer 18

if number occurs twice or more in a array then what will be the output?

Answer 19

Efficient coding challenge https://www.sololearn.com/discuss/637973/?ref=app

Answer 20

MY NEW *DAILY CHALLENGE*:
GIVE IT A TRY!!!

https://www.sololearn.com/discuss/647083/?ref=app