Problem 44067. The last non-zero digit of a factorial

Created by Jihye Sofia Seo

Solve Later

{"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","relationshipId":"rId1","target":"/matlab/document.xml"},{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/output","relationshipId":"rId2","target":"/matlab/output.xml"}],"parts":[{"partUri":"/matlab/document.xml","relationship":[],"contentType":"application/vnd.mathworks.matlab.code.document+xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\"?><w:document xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\"><w:body><w:p><w:pPr><w:pStyle w:val=\"text\"/></w:pPr><w:r><w:t>For given positive integer n, what is the last non-zero digit of n!?</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>Example: factorial(11) = 39916800</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>Last non-zero digit is 8.</w:t></w:r></w:p><w:p><w:pPr><w:pStyle w:val=\"text\"/><w:jc w:val=\"left\"/></w:pPr><w:r><w:t>Optional: Can you make an efficient algorithm for very large n?</w:t></w:r></w:p></w:body></w:document>"},{"partUri":"/matlab/output.xml","contentType":"text/xml","content":"<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?><embeddedOutputs><metaData><evaluationState>manual</evaluationState><layoutState>code</layoutState><outputStatus>ready</outputStatus></metaData><outputArray type=\"array\"/><regionArray type=\"array\"/></embeddedOutputs>"}]}

Solve

Solution Stats

68 Solutions
45 Solvers

Last Solution submitted on Sep 15, 2020

Last 200 Solutions

Problem Comments

Solution Comments

Solution 1124528

1 Comment

1 Comment

James on 16 Feb 2017

Need a better test suite to prevent cheesy solutions like this one. :-) Some N>10 values in there would help. N>50 would be even better.

Problem Recent Solvers45

Problem Tags

factorial

Problem 44067. The last non-zero digit of a factorial

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers45

Suggested Problems

More from this Author9

Problem Tags

Problem 44067. The last non-zero digit of a factorial

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers45

Suggested Problems

More from this Author9

Problem Tags

Players