Problem 1307. RPN Calculator for simple arithmetic expressions

Created by Muthu Annamalai

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{"parts":[{"partUri":"/matlab/document.xml","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:jc w:val=\"left\"/></w:pPr><w:r><w:t>Reverse-Polish-Notation (RPN) is a machine friendly form of calculating expressions. Example, to evaluate, (1+2)*4 + 5 - 3 you enter the sequence into the calculator as, '5 1 2 + 4 * + 3 -' and obtain the result.</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>For this challenge write a RPN calculator for simple arithmetic expressions, '+','-','*','%','/'</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>Note: Chosen interpretations of operators, illustrated from first few test cases, are as follows: rpn('a','b','-') is interpreted as 'a-b', while rpn('a','b','/') is interpreted as 'b/a'. and rpz('a','b','%') which is interpreted as 'b%a'.</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>with operator '%' 'b % a' being mod(b,a) operator.</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>Following your 'stack' solution to</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"\"><w:r><w:t>http://www.mathworks.com/matlabcentral/cody/problems/1303-is-the-paranthesis-sequence-balanced</w:t></w:r></w:hyperlink><w:r><w:t> try using a expression, and a value stack to work this problem.</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>Hint:</w:t></w:r><w:r><w:t> </w:t></w:r><w:hyperlink w:docLocation=\"\"><w:r><w:t>http://en.wikipedia.org/wiki/Reverse_Polish_notation</w:t></w:r></w:hyperlink></w:p></w:body></w:document>","relationship":null}],"relationships":[{"relationshipType":"http://schemas.mathworks.com/matlab/code/2013/relationships/document","target":"/matlab/document.xml","relationshipId":"rId1"}]}

<div style = "text-align: start; line-height: 20.4333px; min-height: 0px; white-space: normal; color: rgb(0, 0, 0); font-family: Menlo, Monaco, Consolas, monospace; font-style: normal; font-size: 14px; font-weight: 400; text-decoration: rgb(0, 0, 0); white-space: normal; "><div style="block-size: 234px; display: block; min-width: 0px; padding-block-start: 0px; padding-top: 0px; perspective-origin: 407px 117px; transform-origin: 407px 117px; vertical-align: baseline; "><div style="block-size: 42px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 21px; text-align: left; transform-origin: 384px 21px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; "><span style="block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 384px 8px; transform-origin: 384px 8px; unicode-bidi: normal; "><span style="">Reverse-Polish-Notation (RPN) is a machine friendly form of calculating expressions. Example, to evaluate, (1+2)*4 + 5 - 3 you enter the sequence into the calculator as, '5 1 2 + 4 * + 3 -' and obtain the result.</span></span></div><div style="block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; "><span style="block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 276px 8px; transform-origin: 276px 8px; unicode-bidi: normal; "><span style="">For this challenge write a RPN calculator for simple arithmetic expressions, '+','-','*','%','/'</span></span></div><div style="block-size: 42px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 21px; text-align: left; transform-origin: 384px 21px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; "><span style="block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 377px 8px; transform-origin: 377px 8px; unicode-bidi: normal; "><span style="">Note: Chosen interpretations of operators, illustrated from first few test cases, are as follows: rpn('a','b','-') is interpreted as 'a-b', while rpn('a','b','/') is interpreted as 'b/a'. and rpz('a','b','%') which is interpreted as 'b%a'.</span></span></div><div style="block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; "><span style="block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 155.5px 8px; transform-origin: 155.5px 8px; unicode-bidi: normal; "><span style="">with operator '%' 'b % a' being mod(b,a) operator.</span></span></div><div style="block-size: 42px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 21px; text-align: left; transform-origin: 384px 21px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; "><span style="block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 101.5px 8px; transform-origin: 101.5px 8px; unicode-bidi: normal; "><span style="">Following your 'stack' solution to</span></span><span style="block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 2px 8px; transform-origin: 2px 8px; unicode-bidi: normal; "><span style=""> </span></span><a target='_blank' href = "/#null"><span style=""><span style="">http://www.mathworks.com/matlabcentral/cody/problems/1303-is-the-paranthesis-sequence-balanced</span></span></a><span style="block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 197.5px 8px; transform-origin: 197.5px 8px; unicode-bidi: normal; "><span style=""> try using a expression, and a value stack to work this problem.</span></span></div><div style="block-size: 21px; font-family: Helvetica, Arial, sans-serif; line-height: 21px; margin-block-end: 9px; margin-block-start: 2px; margin-bottom: 9px; margin-inline-end: 10px; margin-inline-start: 4px; margin-left: 4px; margin-right: 10px; margin-top: 2px; perspective-origin: 384px 10.5px; text-align: left; transform-origin: 384px 10.5px; white-space: pre-wrap; margin-left: 4px; margin-top: 2px; margin-bottom: 9px; margin-right: 10px; "><span style="block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 14px 8px; transform-origin: 14px 8px; unicode-bidi: normal; "><span style="">Hint:</span></span><span style="block-size: auto; display: inline; margin-block-end: 0px; margin-block-start: 0px; margin-bottom: 0px; margin-inline-end: 0px; margin-inline-start: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; perspective-origin: 2px 8px; transform-origin: 2px 8px; unicode-bidi: normal; "><span style=""> </span></span><a target='_blank' href = "/#null"><span style=""><span style="">http://en.wikipedia.org/wiki/Reverse_Polish_notation</span></span></a></div></div></div>

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Last Solution submitted on Mar 22, 2022

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Alfonso Nieto-Castanon on 1 Mar 2013

in your test suite it seems odd that rpz('a','b','-') is interpreted as 'a-b' while rpz('a','b','/') is interpreted as 'b/a' (instead of 'a/b'). Same goes for rpz('a','b','%') which is interpreted as 'b%a' instead of 'a%b'. Last, your last test case rpn(z(1),'+',z(2),'*',z(1),z(3),'-',z(4),z(5),'%','*') is plain weird... it should probably read rpn(z(1),z(2),'+',z(1),'*',z(3),'-',z(4),z(5),'%','*') instead...

Muthu Annamalai on 2 Mar 2013

Thank you for your comments; I will update the description and fix last test case.

Muthu Annamalai on 22 Mar 2013

I will retire the last test case for the problem.

Baki on 6 Nov 2016

I have an rpn solver but it only accepts strings

ChrisR on 21 Aug 2022

Would someone please check the first test? The variable z is commented out.

Dyuman Joshi on 21 Aug 2022

Chris, the format of the test cases has been corrected, you can attempt the question now.

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Problem 1307. RPN Calculator for simple arithmetic expressions

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Problem 1307. RPN Calculator for simple arithmetic expressions

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