#define PERM 13122

'Between any two adjacent digits there can be nothing, a plus, or a minus.
'And the first term can only be + or -
'This is equivalent to an eight-digit base 3 number. We therefore only need
'to consider 2*3^8=13122 possibilities

function ndig(n as uinteger) as uinteger
    return 1+int(log(n+0.5)/log(10))
end function

function calculate( byval n as uinteger, outstr as string ) as integer
    'calculates the sum given by one of the 13122 possibilities, as well as
    'storing the equation itself as a string
    outstr = "9"
    dim as integer ret = 0, curr = 9
    dim as boolean firstplus = n>=PERM/2
    for i as integer = 8 to 1 step -1
        select case n mod 3
            case 0   'no symbol means we just prepend the next number
                curr += i*10^(ndig(curr))
            case 1   'addition: add the current term to the running sum, and clear the current term
                ret += curr
                curr = i
                outstr = " + " + outstr
            case 2   'subtraction: minus the current term from the running sum, and clear the current term
                ret -= curr
                curr = i
                outstr = " - " + outstr
        end select
        outstr = str(i) + outstr      'prepend the previous digit to the string
        n \= 3                        'get next symbol
    next i
    if firstplus = 0 then
        outstr = "-"+outstr
        ret -= curr
    else
        ret += curr
    end if
    outstr = outstr + " = " + str(ret)
    return ret
end function

'calculate and store all 13122 solutions
dim as string eqn
dim as integer n, sum(0 to PERM-1), curr
for n = 0 to PERM-1
    curr = calculate(n, eqn)
    sum(n) = curr
    if curr = 100 then print eqn
next n

'what is the sum that has the most solutions?
dim as integer champ = 0, cnum = 0, i, j, acc
for i = 0 to PERM-1
    acc = 0
    for j = i to PERM-1
        if sum(j) = sum(i) then acc+=1
    next j
    if acc>cnum then
        champ = sum(i)
        cnum=acc
    end if
next i
print "The sum with the most occurrences is ";champ;", which shows up ";cnum;" times."

'what is the first nonnegative number that has no solution
for i = 0 to 123456788
    for j = 0 to PERM-1
        if sum(j)=i then goto nexti
    next j
    print "The first number that has no solution is ";i
    exit for
    nexti:
next i

'What are the ten highest numbers?
'this partially destroys the information in the array, but who cares?
'We're almost done and these excessive questionnaires are the worst
'and most boring part of Rosetta Code tasks

print "The ten highest numbers attainable are:"
champ = 0
for i = 1 to 10
    for j = 0 to PERM-1
        if sum(j)>sum(champ) then champ = j
    next j
    calculate(champ, eqn)
    print eqn
    sum(champ) = -9999   'overwrite to stop this being found a second time
next i