How can I create a big loop like from 0 to range of Long?

Question

The below given code is taking so much time to execute code correct answer

for(long i=0;i<9223372036854775807;i++){
   //code
}

Can anyone tell me any alternative approach or correction of this version?

You could use Long.MAX_VALUE – Shar1er80 Jul 21 '18 at 18:58 — Shar1er80, Jul 21 '18 at 18:58
Why would you want to loop that many times anyway? – 0xCursor Jul 21 '18 at 19:00 — 0xCursor, Jul 21 '18 at 19:00

score 2 · Answer 1 · answered Jul 21 '18 at 18:59

2

from this answer https://stackoverflow.com/a/15505663/7806805 and since your question is

The below given code is taking so much time to execute code correct answer

If you were executing your function once per nanosecond, it would still take over 292 years to encounter this situation according to this source.

so its natural for it to take time

answered Jul 21 '18 at 18:59

Ishan Srivastava

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Then what is alternative approach I can use rather than this? – Ishdeep Singh Jul 22 '18 at 05:39

GhostCat · Accepted Answer · 2018-07-21T19:11:39.883

The one change you could make is to use the constant Long.MAX_VALUE instead.

But don't expect that to change anything. That loop still takes all the time it takes to iterate that range.

In other words: how you express "I want to iterate 2 to the power of 63 minus 1" times doesn't influence the time required to do that at all.

The only thing to cut runtime is by slicing the range and have multiple smaller loops go in parallel. But of course: without any detail on the loop body it is not possible to determine whether parallelism is applicable here.

And of course, the real question would be about the actual problem that you intend to solve by iterating code for millions, billions of years.

score -1 · Answer 3 · answered Jul 21 '18 at 18:58

-1

I suggest to use Long.MAX_VALUE as a loop bound:

for(long i=0L;i<Long.MAX_VALUE;i++){
//code
  }

answered Jul 21 '18 at 18:58

Mustapha Belmokhtar

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You pretty much just said what Shar1er80 said in his comment. – 0xCursor Jul 21 '18 at 18:59
1

The OP's concern is that his program is taking too much time. Not this. – Ishan Srivastava Jul 21 '18 at 19:00
@LAD to be honset, I didn't copy his comment :D – Mustapha Belmokhtar Jul 21 '18 at 19:00
Yeah that's pretty obvious, for sure, it'll take a huge time to be done. – Mustapha Belmokhtar Jul 21 '18 at 19:03

How can I create a big loop like from 0 to range of Long?

3 Answers3