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Fix Stack pop comlexity to be O(1) #214

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Merged
merged 1 commit into from
Sep 24, 2018
Merged

Fix Stack pop comlexity to be O(1) #214

merged 1 commit into from
Sep 24, 2018

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yavorski
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  • By definition Stack push/pop time complexity should be O(1).
  • Fix is applied by removing head instead of tail in pop method.
  • Push method now do preprend instead of append.
  • Fix consistency between toString and toArray methods.

Fix Stack pop comlexity to be O(1)
86660ec 
* By definition Stack push/pop time complexity should be O(1).
* Fix is applied by removing head instead of tail in pop method.
* Push method now do preprend instead of append.
* Fix consistency between toString and toArray methods.
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codecov bot commented Sep 23, 2018

Codecov Report

Merging #214 into master will not change coverage.
The diff coverage is 100%.

Impacted file tree graph

@@          Coverage Diff          @@
##           master   #214   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files         143    143           
  Lines        2555   2555           
  Branches      422    422           
=====================================
  Hits         2555   2555
Impacted Files Coverage Δ
src/data-structures/stack/Stack.js 100% <100%> (ø) ⬆️

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@yavorski
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yavorski commented Sep 23, 2018 •
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Leaving a small note here:

I noticed that pop method of the Stack is using deleteTail method of a LinkedList, which has a time complexity of O(n).

Due to this fact - I refactored it to use deleteHead, which has a complexity of O(1).
In addition to this push is now using prepend instead of append.

This commit also fixes the consistency of toArray vs toString methods of the Stack, which are printing the stack in different ways.

Best of luck,
Yavorski

@trekhleb
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@yavorski thank you for your refactoring! Good job!

@trekhleb trekhleb merged commit 9f3561d into trekhleb:master Sep 24, 2018
harshes53 pushed a commit to harshes53/javascript-algorithms that referenced this pull request Dec 6, 2018
@harshes53
Fix Stack pop comlexity to be O(1) (trekhleb#214)
ec45a15 
* By definition Stack push/pop time complexity should be O(1).
* Fix is applied by removing head instead of tail in pop method.
* Push method now do preprend instead of append.
* Fix consistency between toString and toArray methods.
shoredata pushed a commit to shoredata/javascript-algorithms that referenced this pull request Mar 28, 2019
@shoredata
Fix Stack pop comlexity to be O(1) (trekhleb#214)
39f6ffe 
* By definition Stack push/pop time complexity should be O(1).
* Fix is applied by removing head instead of tail in pop method.
* Push method now do preprend instead of append.
* Fix consistency between toString and toArray methods.
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@yavorski @trekhleb