Distinct palindromes within decimal numbers: Difference between revisions

=={{header|Nim}}==

<lang Nim>import algorithm, sequtils, sets, strutils

iterator substrings(s: string): string =

## Yield the substrings of the given string.

for istart in 0..s.high:

for istop in istart..s.high:

yield s[istart..istop]

func isPalindrome(s: string): bool =

## Return true if "s" is a palindrome.

result = true

for i in 0..(s.high div 2):

if s[i] != s[s.high - i]: return false

func cmpPal(s1, s2: string): int =

## Compare two palindromes (used for sort).

result = cmp(s1.len, s2.len)

if result == 0:

result = cmp(s1[0], s2[0])

func palindromes(str: string): seq[string] =

## Return the sorted list of palindromes contained in "str".

var palSet: HashSet[string]

for s in substrings(str):

if s.isPalindrome: palSet.incl s

result = sorted(toSeq(palSet), cmpPal)

when isMainModule:

for n in 100..125:

echo n, ": ", palindromes($n).mapIt(it.align(3)).join(" ")

echo()

for s in ["9", "169", "12769", "1238769", "123498769", "12346098769",

"1234572098769", "123456832098769", "12345679432098769",

"1234567905432098769", "123456790165432098769",

"83071934127905179083", "1320267947849490361205695"]:

let pals2 = palindromes(s).filterIt(it.len >= 2)

let verb = if pals2.len == 0: " doesn't contain palindromes "

else: " contains at least one palindrome "

echo s, verb, "of two digits or more"</lang>

{{out}}

<pre>100: 0 1 00

101: 0 1 101

102: 0 1 2

103: 0 1 3

104: 0 1 4

105: 0 1 5

106: 0 1 6

107: 0 1 7

108: 0 1 8

109: 0 1 9

110: 0 1 11

111: 1 11 111

112: 1 2 11

113: 1 3 11

114: 1 4 11

115: 1 5 11

116: 1 6 11

117: 1 7 11

118: 1 8 11

119: 1 9 11

120: 0 1 2

121: 1 2 121

122: 1 2 22

123: 1 2 3

124: 1 2 4

125: 1 2 5

9 doesn't contain palindromes of two digits or more

169 doesn't contain palindromes of two digits or more

12769 doesn't contain palindromes of two digits or more

1238769 doesn't contain palindromes of two digits or more

123498769 doesn't contain palindromes of two digits or more

12346098769 doesn't contain palindromes of two digits or more

1234572098769 doesn't contain palindromes of two digits or more

123456832098769 doesn't contain palindromes of two digits or more

12345679432098769 doesn't contain palindromes of two digits or more

1234567905432098769 doesn't contain palindromes of two digits or more

123456790165432098769 doesn't contain palindromes of two digits or more

83071934127905179083 doesn't contain palindromes of two digits or more

1320267947849490361205695 contains at least one palindrome of two digits or more</pre>