factors
Segmented Sieve of Eratosthenes?
The basic idea of a segmented sieve is to choose the sieving primes less than the square root of n, choose a reasonably large segment size that nevertheless fits in memory, and then sieve each of the segments in turn, starting with the smallest. At the first segment, the smallest multiple of each sieving prime … Read more
Why is my Swift loop failing with error “Can’t form range with end < start"?
Swift 5 If you need a loop with dynamic value-range, I suggest that using stride(to:by:) instead of ..< or … Basically ..< or … will be crashed if start_index > end_index. This will be crash: let k = 5 for i in 10…k { print(“i=\(i)”) } for i in 10..<k { print(“i=\(i)”) } How to … Read more
nᵗʰ ugly number
A simple fast solution in Java. Uses approach described by Anon.. Here TreeSet is just a container capable of returning smallest element in it. (No duplicates stored.) int n = 20; SortedSet<Long> next = new TreeSet<Long>(); next.add((long) 1); long cur = 0; for (int i = 0; i < n; ++i) { cur = next.first(); … Read more