string n = "000000"

function incn()
    for i=length(n) to 1 by -1 do
        if n[i]='9' then
            if i=1 then return false end if
            n[i]='0'
        else
            n[i] += 1
            exit
        end if
    end for
    return true
end function

sequence res = {}, bestseen
integer maxcycle = 0

procedure srs()
sequence seen, this = n
integer cycle = 1
    while length(this)>1 and this[1]='0' do
        this = this[2..$]
    end while
    integer ch = this[1]
    for i=2 to length(this) do
        if this[i]>ch then return end if
        ch = this[i]
    end for
    seen = {this}
    while 1 do
        sequence digits = repeat(0,10)
        for i=1 to length(this) do
            digits[this[i]-'0'+1] += 1
        end for
        string next = ""
        for i=length(digits) to 1 by -1 do
            if digits[i]!=0 then
                next &= sprint(digits[i])
                next &= i+'0'-1
            end if
        end for
        if find(next,seen) then exit end if
        seen = append(seen,next)
        this = next
        cycle += 1
    end while
    if cycle>maxcycle then
        res = {seen[1]}
        maxcycle = cycle
        bestseen = seen
    elsif cycle=maxcycle then
        res = append(res,seen[1])
    end if
end procedure

while 1 do
    srs()
    if not incn() then exit end if
end while

-- add non-leading-0 perms:
for i=length(res) to 1 by -1 do
    string ri = res[i]
    for p=1 to factorial(length(ri)) do
        string pri = permute(p,ri)
        if pri[1]!='0' and not find(pri,res) then
            res = append(res,pri)
        end if
    end for
end for
?res
puts(1,"cycle length is ") ?maxcycle
pp(bestseen,{pp_Nest,1})