Question: Problem of parsing binary number

This is my source code to perform several binary arithmetic and HUffman Compression

Freq := proc (s) options operator, arrow; map(proc (x) options operator, arrow; rhs(x) = lhs(x) end proc, {StringTools:-CharacterFrequencies(s)}) end proc; s := readstat("x will be assigned "); Fr := Freq(s);

algo
{1 = "a", 1 = "g", 1 = "l", 1 = "o"}

HuffmanTree := proc (s) options operator, arrow; if nops(s) <= 1 then rhs(s[]) else procname(`union`(s[3 .. -1], {lhs(s[1])+lhs(s[2]) = [rhs(s[1]), rhs(s[2])]})) end if end proc; HT := HuffmanTree(Fr);

[["a", "g"], ["l", "o"]]

HuffmanCoding := proc (s, p := "") if s::string then s = p else procname(s[1], cat(p, 0)), procname(s[2], cat(p, 1)) end if end proc; HC := HuffmanCoding(HT);

"a" = "00", "g" = "01", "l" = "10", "o" = "11"

C := table([HC]); b := cat(map(proc (x) options operator, arrow; C[x] end proc, StringTools:-Explode(s))[]);

"00100111"

# Begin the procedure with make string to integer
z := parse(b);

                                                                   100111    #Should be 00100111 after parsing

# Step 1:add 1 to z
binaryAdd := proc (z, y) options operator, arrow; convert(convert(z, decimal, 2)+convert(y, decimal, 2), binary) end proc;
z1 := binaryAdd(z, 1);

101000

# Step 2: Reverse the number from left to right
z2 := convert(z1, base, 10);

[0, 0, 0, 1, 0, 1]

z3 := (parse@cat@op)(z2);

                                                                101  #Should be 000101 after parsing

 # Step 3: Addition between the first secret key and the Huffman Code

randomize();

p := rand(0 .. 2^(length(z3)-2)):

rn := convert(p(), binary);

1

z4 := binaryAdd(z3, rn);

110

# Step 4:Obtain 2's complement

s := length(z4);

z5 := convert(z4, decimal, binary);

6

z6 := [Bits:-GetBits(-z5, -1 .. 0, bits = s)];

[0, 1, 0]

z7 :=(parse@cat@op)(z6);

                                                       10  # Should be 010 after passing

The Bold part is MAPLE answer. My problem for this MAPLE source code is the underlined answer  as I can't get the answer I need after I have my parsing of string or list. Do this problem can be solved or it is impossible to make the leading zero all the way of the process. I try to figure it out for several solution but it still the same results. Thus hope some experts or someone can help me solve it together. Appreciated if get solved.