project-euler/Yet to solve/862 Larger Digit Permutation.sf

#!/usr/bin/ruby

# Larger Digit Permutation
# https://projecteuler.net/problem=862

var k = 3
var sum = 0

for n in (10**(k-1) .. (10**k - 1)) {
    var D = n.digits.flip

    var count = 0

    loop {
        say [count, D.flip.digits2num]
        D.next_permutation || break
        count += 1
    }

    say ''
    sum += count
}

say sum