41 lines
1.1 KiB
Plaintext
41 lines
1.1 KiB
Plaintext
fn hailstone(start : u32) -> Vec<u32> {
|
|
let mut res = Vec::new();
|
|
let mut next = start;
|
|
|
|
res.push(start);
|
|
|
|
while next != 1 {
|
|
next = if next % 2 == 0 { next/2 } else { 3*next+1 };
|
|
res.push(next);
|
|
}
|
|
res
|
|
}
|
|
|
|
|
|
fn main() {
|
|
let test_num = 27;
|
|
let test_hailseq = hailstone(test_num);
|
|
|
|
println!("For {} number of elements is {} ", test_num, test_hailseq.len());
|
|
|
|
let fst_slice = test_hailseq[0..4].iter()
|
|
.fold("".to_owned(), |acc, i| { acc + &*(i.to_string()).to_owned() + ", " });
|
|
let last_slice = test_hailseq[test_hailseq.len()-4..].iter()
|
|
.fold("".to_owned(), |acc, i| { acc + &*(i.to_string()).to_owned() + ", " });
|
|
|
|
println!(" hailstone starting with {} ending with {} ", fst_slice, last_slice);
|
|
|
|
let max_range = 100000;
|
|
let mut max_len = 0;
|
|
let mut max_seed = 0;
|
|
for i_seed in 1..max_range {
|
|
let i_len = hailstone(i_seed).len();
|
|
|
|
if i_len > max_len {
|
|
max_len = i_len;
|
|
max_seed = i_seed;
|
|
}
|
|
}
|
|
println!("Longest sequence is {} element long for seed {}", max_len, max_seed);
|
|
}
|