solution is so simple, and I created such a monster, lol

measuring the same way as above, hopefully correctly ( on w3schools.com)

time in ms: 256

time in ms: 202

time in ms: 187

time in ms: 187

time in ms: 187

time in ms: 187

time in ms: 187

time in ms: 187

time in ms: 188

time in ms: 187

anyway, I guess now I can see, my solution could be probably more efficient

come on...
I am measuring the same code on w3schools compiler....
it gives me less then 100 ms....

time in ms: 54

time in ms: 35

time in ms: 34

time in ms: 34

time in ms: 34

time in ms: 34

time in ms: 34

time in ms: 35

time in ms: 34

time in ms: 34

public static void main(String[] args) {

for (int i = 0; i < 10; i++)

	measureExecutionTime();

}

public static void measureExecutionTime() {

long start1 = System.nanoTime();

int n = 14262805;

String f = factors(n);

long start2 = System.nanoTime();

long ms = (start2 - start1)/1_000_000;

System.out.println("time in ms: " +  ms);

}

Execution Timed Out (16000 ms)

oh, come on.... tests are passed, I just need few millis more....

it's not hanging forever, anyway...

completely gave up on this one...

by default Math.pow method returns result of type double...

so there might be truly an error in those tests...

perhaps method findNb should return double and not long...

it is very interesting it seems that starting from n = 32768

there are different results for type long (r1) and double (r2)...

which result is true then...?

.

.

.

n=32765, r1=288142425153114400, r2=288142425153114400.000000

n=32766, r1=288177603083145504, r2=288177603083145504.000000

n=32767, r1=288212784234107168, r2=288212784234107168.000000

n=32768, r1=288247968606195968, r2=288247968606195970.000000

n=32769, r1=288283156199608576, r2=288283156199608580.000000

n=32770, r1=288318347014541568, r2=288318347014541570.000000

n=32771, r1=288353541051191552, r2=288353541051191550.000000

n=32772, r1=288388738309755200, r2=288388738309755200.000000
.
.
.

However I still do not understand how it works,

I added type casting to my previous solution, because, when trying to test failing solution,

compiler gave me warning,

but we are summig integers in both cases, so why it does not work...

.

thank you for the tip!

why it's not enough, to check wether list of characters from str1, containsAll characters from str2 ?