Longest substrings without repeating characters

Longest substrings without repeating characters is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Task

Given a string find the longest substring without repeating characters.

Ring

<lang ring> see "working..." + nl see "Longest substrings without repeating characters are:" + nl str = "xyzyabcybdfd" see "Input: " + str + nl lenStr = len(str) strOk = [] lenOk = 0

for n = 1 to lenStr

   for m = 1 to lenStr-n+1
       temp = substr(str,n,m)
       add(strOk,temp)
   next

next

for n = len(strOk) to 1 step -1

   if len(strOK[n]) = 1
      del(strOK,n)
   ok

next

for n = 1 to len(strOK)

   for m = 1 to len(strOK)-1
       if len(strOK[m+1]) > len(strOK[m])
          temp = strOK[m]
          strOK[m] = strOK[m+1]
          strOK[m+1] = temp
       ok
   next

next

for n = 1 to len(strOK)

   flag = 1
   for m = 1 to len(strOK[n])
       for p = m+1 to len(strOK[n])
           if strOK[n][m] = strOK[n][p]
              flag = 0
              exit
           ok
       next
   next
   if flag = 1
      if len(strOK[n]) >= lenOk
         see "len = " + len(strOK[n]) + " : " + strOK[n] + nl
         lenOK = len(strOK[n])
      ok
   ok

next

see "done..." + nl </lang>

Output:

working...
Longest substrings without repeating characters are:
Input: xyzyabcybdfd
len = 5 : zyabc
len = 5 : cybdf
done...

Wren

<lang ecmascript>import "/seq" for Lst

var substrings = Fn.new { |s|

   var n = s.count
   if (n == 0) return [""]
   var ss = []
   for (i in 0...n) {
       for (len in 1..n-i) ss.add(s[i...i+len])
   }
   return ss

}

System.print("The longest substring(s) of the following without repeating characters are:\n") var strs = ["xyzyabcybdfd", "xyzyab", "zzzzz", "a", "", ] for (s in strs) {

   var longest = []
   var longestLen = 0
   for (ss in substrings.call(s)) {
       if (Lst.distinct(ss.toList).count == ss.count) { 
           if (ss.count >= longestLen) {
               if (ss.count > longestLen) {
                   longest.clear()
                   longestLen = ss.count
               }
               longest.add(ss.join())
           }
       }
   }

   longest = Lst.distinct(longest)
   System.print("String = '%(s)'")
   System.print(longest)
   System.print("Length = %(longest[0].count)\n")

}</lang>

Output:

The longest substring(s) of the following without repeating characters are:

String = 'xyzyabcybdfd'
[zyabc, cybdf]
Length = 5

String = 'xyzyab'
[zyab]
Length = 4

String = 'zzzzz'
[z]
Length = 1

String = 'a'
[a]
Length = 1

String = ''
[]
Length = 0