Largest palindrome product: Difference between revisions
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<lang Mathematica>palindromeQ[n_] := |
<lang Mathematica>palindromeQ[n_] := |
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Block[{digits = IntegerDigits@n}, digits == Reverse[digits]] |
Block[{digits = IntegerDigits@n}, digits == Reverse[digits]] |
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nextPair[n_] := |
nextPair[n_] := |
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⚫ | |||
⚫ | |||
NestWhile[# - 11 &, n, ! MemberQ[{1, 3, 7, 9}, Mod[#, 10]] &], |
NestWhile[# - 11 &, n, ! MemberQ[{1, 3, 7, 9}, Mod[#, 10]] &], |
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len = Last@RealDigits@n}, |
len = Last@RealDigits@n}, |
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{next, 10^len - Switch[Mod[next, 10], 1, 1, 3, 7, 7, 3, 9, 9]}] |
{next, 10^len - Switch[Mod[next, 10], 1, 1, 3, 7, 7, 3, 9, 9]}] |
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search[n_] := |
search[n_] := |
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Block[{resetLimit = 10^(n - Floor[n/2]) (10^Floor[n/2] - 1), cands}, |
Block[{resetLimit = 10^(n - Floor[n/2]) (10^Floor[n/2] - 1), cands}, |
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cands = |
cands = |