fn main() { let mut i: u64 = 0; let mut v: u64; let mut highest = u64::MIN; loop { i += 1; v = i; loop { // Is even if v % 2 == 0 { v /= 2; } else { v = 3 * v + 1; } if v > highest { highest = v; } if v == 1 { if i % 1_000_000 == 0 { println!("{:10}: All Pass | HI {:10}", i, highest); } break; } } } }