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Longest substrings without repeating characters: Difference between revisions
Longest substrings without repeating characters (view source)
Revision as of 06:38, 28 May 2021
, 3 years agoAdd Python
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"[1, 2, 3, 4, 1, 2, 5, 6, 1, 7, 8, 1, 0]" => [[3, 4, 1, 2, 5, 6], [2, 5, 6, 1, 7, 8]]
</pre>
=={{header|Python}}==
The following algorithm works but is not terribly efficient for long strings.
<lang python>def longest_substring(s = "xyzyab"):
substr = [s[x:y] for x in range(len(s)) for y in range(x+1, len(s) + 1)]
no_reps = []
for sub in substr:
if len(sub) == len(set(sub)) and sub not in no_reps:
no_reps.append(sub)
max_len = max(len(sub) for sub in no_reps) if no_reps else 0
max_subs = [sub for sub in no_reps if len(sub) == max_len]
return max_subs
if __name__ == '__main__':
for s in ["xyzyabcybdfd", "xyzyab", "zzzzz", "a", "α⊆϶α϶", "",
[1, 2, 3, 4, 1, 2, 5, 6, 1, 7, 8, 1, 0]]:
print(f"{s} => {longest_substring(s)}")
</lang>
{{out}}
<pre>xyzyabcybdfd => ['zyabc', 'cybdf']
xyzyab => ['zyab']
zzzzz => ['z']
a => ['a']
α⊆϶α϶ => ['α⊆϶', '⊆϶α']
=> []
[1, 2, 3, 4, 1, 2, 5, 6, 1, 7, 8, 1, 0] => [[3, 4, 1, 2, 5, 6], [2, 5, 6, 1, 7, 8]]</pre>
=={{header|Raku}}==
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