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Swift Prims algorithm

Generating Phone Words in SwiftDot product, ported from C to SwiftQuickselect algorithm in SwiftDFT (Discrete Fourier Transform) Algorithm in SwiftImplementation of a piece table in SwiftSelection sort algorithm in SwiftNavigation controller in SwiftSwift Throttler and DebouncerFinding valid path on 2D GridDijkstra algorithm implementation in Swift

0

$begingroup$

Lots of Prims algorithm implementations seem long, and rely on a priority queue implementation.

If I use an adjacency matrix I can then calculate the next item to take using functional programming in Swift.

func prims (_ matrix : [[Int]]) 
 var selected = 0
 var selectedSoFar = Set<Int>()
 selectedSoFar.insert( (matrix[selected].enumerated().min $0.element < $1.element ?.offset)! )

 while selectedSoFar.count < matrix.count 
 var minValue = Int.max
 var minIndex = selected
 var initialRow = 0
 for row in selectedSoFar 
 let candidateMin = matrix[row].enumerated().filter$0.element > 0 && !selectedSoFar.contains($0.offset) .min $0.element < $1.element 
 if (minValue > candidateMin?.element ?? Int.max ) 
 minValue = candidateMin?.element ?? Int.max
 minIndex = (candidateMin?.offset) ?? 0
 initialRow = row
 
 
 print ("edge value (minValue) with (initialRow) to (minIndex)")
 selectedSoFar.insert(minIndex)
 selected = (minValue)
 


let input = [[0,9,75,0,0],[9,0,95,19,42],[75,95,0,51,66],[0,19,51,0,31],[0,42,66,31,0]]
prims(input)

Essentially is there anything "wrong" with this implementation? This is not homework, my code runs correctly for the included output and I appreciate this is faster if I use an adjacency matrix. However the Ray Wenderlich implementation of Prims uses 7 files and >200 lines of code. Am I missing something?

swift

share

asked 3 mins ago

WishIHadThreeGunsWishIHadThreeGuns

1

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add a comment | 

0

$begingroup$

Lots of Prims algorithm implementations seem long, and rely on a priority queue implementation.

If I use an adjacency matrix I can then calculate the next item to take using functional programming in Swift.

func prims (_ matrix : [[Int]]) 
 var selected = 0
 var selectedSoFar = Set<Int>()
 selectedSoFar.insert( (matrix[selected].enumerated().min $0.element < $1.element ?.offset)! )

 while selectedSoFar.count < matrix.count 
 var minValue = Int.max
 var minIndex = selected
 var initialRow = 0
 for row in selectedSoFar 
 let candidateMin = matrix[row].enumerated().filter$0.element > 0 && !selectedSoFar.contains($0.offset) .min $0.element < $1.element 
 if (minValue > candidateMin?.element ?? Int.max ) 
 minValue = candidateMin?.element ?? Int.max
 minIndex = (candidateMin?.offset) ?? 0
 initialRow = row
 
 
 print ("edge value (minValue) with (initialRow) to (minIndex)")
 selectedSoFar.insert(minIndex)
 selected = (minValue)
 


let input = [[0,9,75,0,0],[9,0,95,19,42],[75,95,0,51,66],[0,19,51,0,31],[0,42,66,31,0]]
prims(input)

Essentially is there anything "wrong" with this implementation? This is not homework, my code runs correctly for the included output and I appreciate this is faster if I use an adjacency matrix. However the Ray Wenderlich implementation of Prims uses 7 files and >200 lines of code. Am I missing something?

swift

share

asked 3 mins ago

WishIHadThreeGunsWishIHadThreeGuns

1

New contributor

WishIHadThreeGuns is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

add a comment | 

$begingroup$

Lots of Prims algorithm implementations seem long, and rely on a priority queue implementation.

If I use an adjacency matrix I can then calculate the next item to take using functional programming in Swift.

func prims (_ matrix : [[Int]]) 
 var selected = 0
 var selectedSoFar = Set<Int>()
 selectedSoFar.insert( (matrix[selected].enumerated().min $0.element < $1.element ?.offset)! )

 while selectedSoFar.count < matrix.count 
 var minValue = Int.max
 var minIndex = selected
 var initialRow = 0
 for row in selectedSoFar 
 let candidateMin = matrix[row].enumerated().filter$0.element > 0 && !selectedSoFar.contains($0.offset) .min $0.element < $1.element 
 if (minValue > candidateMin?.element ?? Int.max ) 
 minValue = candidateMin?.element ?? Int.max
 minIndex = (candidateMin?.offset) ?? 0
 initialRow = row
 
 
 print ("edge value (minValue) with (initialRow) to (minIndex)")
 selectedSoFar.insert(minIndex)
 selected = (minValue)
 


let input = [[0,9,75,0,0],[9,0,95,19,42],[75,95,0,51,66],[0,19,51,0,31],[0,42,66,31,0]]
prims(input)

Essentially is there anything "wrong" with this implementation? This is not homework, my code runs correctly for the included output and I appreciate this is faster if I use an adjacency matrix. However the Ray Wenderlich implementation of Prims uses 7 files and >200 lines of code. Am I missing something?

swift

share

asked 3 mins ago

WishIHadThreeGunsWishIHadThreeGuns

1

New contributor

WishIHadThreeGuns is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

func prims (_ matrix : [[Int]]) 
 var selected = 0
 var selectedSoFar = Set<Int>()
 selectedSoFar.insert( (matrix[selected].enumerated().min $0.element < $1.element ?.offset)! )

 while selectedSoFar.count < matrix.count 
 var minValue = Int.max
 var minIndex = selected
 var initialRow = 0
 for row in selectedSoFar 
 let candidateMin = matrix[row].enumerated().filter$0.element > 0 && !selectedSoFar.contains($0.offset) .min $0.element < $1.element 
 if (minValue > candidateMin?.element ?? Int.max ) 
 minValue = candidateMin?.element ?? Int.max
 minIndex = (candidateMin?.offset) ?? 0
 initialRow = row
 
 
 print ("edge value (minValue) with (initialRow) to (minIndex)")
 selectedSoFar.insert(minIndex)
 selected = (minValue)
 


let input = [[0,9,75,0,0],[9,0,95,19,42],[75,95,0,51,66],[0,19,51,0,31],[0,42,66,31,0]]
prims(input)

share

asked 3 mins ago

WishIHadThreeGunsWishIHadThreeGuns

1

New contributor

WishIHadThreeGuns is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share

asked 3 mins ago

WishIHadThreeGunsWishIHadThreeGuns

1

New contributor

WishIHadThreeGuns is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 3 mins ago

WishIHadThreeGunsWishIHadThreeGuns

1

New contributor

WishIHadThreeGuns is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 3 mins ago

WishIHadThreeGunsWishIHadThreeGuns

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