#/***********************************************************
#    permnum.rb -- 界误
#***********************************************************/
# 极脸眶との陵高恃垂 

N = 4
$a = []

def encode
    c = 0
    N.downto(2) do |i|
        k = 1
        for j in 2..i
            if ($a[j] > $a[k]); k = j; end
        end
        t = $a[i];  $a[i] = $a[k];  $a[k] = t
        c = c * i + k - 1
    end
    return c
end

def decode(c)
    for i in 2..N
        k = c % i + 1;  c /= i
        t = $a[i];  $a[i] = $a[k];  $a[k] = t
    end
end

def nextperm
    $a[0] = 0;  # 戎客 
    i = N - 1
    while ($a[i] >= $a[i + 1]); i -= 1; end
    if (i == 0); return 0; end  # 窗位 
    j = N
    while ($a[i] >= $a[j]); j -= 1; end
    t = $a[i];  $a[i] = $a[j];  $a[j] = t
    i += 1;  j = N
    while (i < j) 
        t = $a[i];  $a[i] = $a[j];  $a[j] = t;  i += 1;  j -= 1
    end
    return 1;  # 踏位 
end

def show(count)
    printf("%5d: ", count)
    for i in 1..N; printf("%4d", $a[i]); end
    printf("\n")
end

count = 0
for i in 1..N; $a[i] = i; end
begin 
    count += 1
    show(count)
    printf("code = %d\n", c = encode)
    show(count)
    decode(c)
    show(count)
    printf("\n")
end while (nextperm() == 1)

exit 0