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Answer by Clark Thomborson for random permutation
See https://doi.org/10.1145/3009909 for a careful analysis of the number of random bits required to generate a random permutation. (It's open-access, but it's not easy reading! Bottom line: if...
View ArticleAnswer by Pauli for random permutation
Are you sure that your mathematical and algorithmical approach to the problem is correct?I hit exactly same problem where Fisher–Yates shuffle will be bottleneck in corner cases. But for me the real...
View ArticleAnswer by ShinTakezou for random permutation
Generate N numbers (N < of the number of random number you need) before to do the computation, or store them in an array as data, with your slow but good random generator; then pick up a number...
View ArticleAnswer by ony for random permutation
Usually there is no need in full-range of next random value, so to use exactly the same amount of randomness you can use next approach (which is almost like random(0,N!), I guess):// ...m = 1; // range...
View ArticleAnswer by user97370 for random permutation
As other answers suggest, you can make a random integer in the range 0 to N! and use it to produce a shuffle. Although theoretically correct, this won't be faster in general since N! grows fast and...
View ArticleAnswer by Nikita Rybak for random permutation
Not what you asked exactly, but if provided random number generator doesn't satisfy you, may be you should try something different. Generally, pseudorandom number generation can be very...
View ArticleAnswer by IVlad for random permutation
Generate a 32 bit integer. For each index i (maybe only up to half the number of elements in the array), if bit i % 32 is 1, swap i with n - i - 1.Of course, this might not be random enough for your...
View ArticleAnswer by aioobe for random permutation
Generating a random number takes long time you say? The implementation of Javas Random.nextInt is roughlyoldseed = seed;nextseed = (oldseed * multiplier + addend) & mask;return (int)(nextseed...
View ArticleAnswer by Aryabhatta for random permutation
Create a 1-1 mapping of each permutation to a number from 1 to n! (n factorial). Generate a random number in 1 to n!, use the mapping, get the permutation.For the mapping, perhaps this will be useful:...
View Articlerandom permutation
I would like to genrate a random permutation as fast as possible.The problem: The knuth shuffle which is O(n) involves generating n random numbers.Since generating random numbers is quite expensive.I...
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