Task: Stable marriage problem




Go: package main

import "fmt"







type proposers map[string][]string
    
var mPref = proposers{
    "abe": []string{
        "abi", "eve", "cath", "ivy", "jan",
        "dee", "fay", "bea", "hope", "gay"},
    "bob": []string{
        "cath", "hope", "abi", "dee", "eve",
        "fay", "bea", "jan", "ivy", "gay"},
    "col": []string{
        "hope", "eve", "abi", "dee", "bea",
        "fay", "ivy", "gay", "cath", "jan"},
    "dan": []string{
        "ivy", "fay", "dee", "gay", "hope",
        "eve", "jan", "bea", "cath", "abi"},
    "ed": []string{
        "jan", "dee", "bea", "cath", "fay",
        "eve", "abi", "ivy", "hope", "gay"},
    "fred": []string{
        "bea", "abi", "dee", "gay", "eve",
        "ivy", "cath", "jan", "hope", "fay"},
    "gav": []string{
        "gay", "eve", "ivy", "bea", "cath",
        "abi", "dee", "hope", "jan", "fay"},
    "hal": []string{
        "abi", "eve", "hope", "fay", "ivy",
        "cath", "jan", "bea", "gay", "dee"},
    "ian": []string{
        "hope", "cath", "dee", "gay", "bea",
        "abi", "fay", "ivy", "jan", "eve"},
    "jon": []string{
        "abi", "fay", "jan", "gay", "eve",
        "bea", "dee", "cath", "ivy", "hope"},
}

type recipients map[string]map[string]int

var wPref = recipients{
    "abi": map[string]int{
        "bob": 1, "fred": 2, "jon": 3, "gav": 4, "ian": 5,
        "abe": 6, "dan": 7, "ed": 8, "col": 9, "hal": 10},
    "bea": map[string]int{
        "bob": 1, "abe": 2, "col": 3, "fred": 4, "gav": 5,
        "dan": 6, "ian": 7, "ed": 8, "jon": 9, "hal": 10},
    "cath": map[string]int{
        "fred": 1, "bob": 2, "ed": 3, "gav": 4, "hal": 5,
        "col": 6, "ian": 7, "abe": 8, "dan": 9, "jon": 10},
    "dee": map[string]int{
        "fred": 1, "jon": 2, "col": 3, "abe": 4, "ian": 5,
        "hal": 6, "gav": 7, "dan": 8, "bob": 9, "ed": 10},
    "eve": map[string]int{
        "jon": 1, "hal": 2, "fred": 3, "dan": 4, "abe": 5,
        "gav": 6, "col": 7, "ed": 8, "ian": 9, "bob": 10},
    "fay": map[string]int{
        "bob": 1, "abe": 2, "ed": 3, "ian": 4, "jon": 5,
        "dan": 6, "fred": 7, "gav": 8, "col": 9, "hal": 10},
    "gay": map[string]int{
        "jon": 1, "gav": 2, "hal": 3, "fred": 4, "bob": 5,
        "abe": 6, "col": 7, "ed": 8, "dan": 9, "ian": 10},
    "hope": map[string]int{
        "gav": 1, "jon": 2, "bob": 3, "abe": 4, "ian": 5,
        "dan": 6, "hal": 7, "ed": 8, "col": 9, "fred": 10},
    "ivy": map[string]int{
        "ian": 1, "col": 2, "hal": 3, "gav": 4, "fred": 5,
        "bob": 6, "abe": 7, "ed": 8, "jon": 9, "dan": 10},
    "jan": map[string]int{
        "ed": 1, "hal": 2, "gav": 3, "abe": 4, "bob": 5,
        "jon": 6, "col": 7, "ian": 8, "fred": 9, "dan": 10},
}

func main() {
    
    ps := pair(mPref, wPref)
    
    fmt.Println("\nresult:")
    if !validateStable(ps, mPref, wPref) {
        return 
    }
    
    for {
        i := 0 
        var w2, m2 [2]string
        for w, m := range ps {
            w2[i] = w
            m2[i] = m
            if i == 1 {
                break
            }
            i++
        }
        fmt.Println("\nexchanging partners of", m2[0], "and", m2[1])
        ps[w2[0]] = m2[1]
        ps[w2[1]] = m2[0] 
        
        if !validateStable(ps, mPref, wPref) {
            return
        }
        
    }
}   

type parings map[string]string 
    

func pair(pPref proposers, rPref recipients) parings {
    
    pFree := proposers{}
    for k, v := range pPref {
        pFree[k] = append([]string{}, v...)
    }
    rFree := recipients{}
    for k, v := range rPref {
        rFree[k] = v
    }
    
    
    type save struct {
        proposer string
        pPref    []string
        rPref    map[string]int
    }
    proposals := map[string]save{} 

    
    
    for len(pFree) > 0 { 
        var proposer string
        var ppref []string
        for proposer, ppref = range pFree {
            break 
        }
        if len(ppref) == 0 {
            continue 
        }
        
        recipient := ppref[0] 
        ppref = ppref[1:]     
        var rpref map[string]int
        var ok bool
        
        if rpref, ok = rFree[recipient]; ok {
            
            
        } else {
            
            s := proposals[recipient] 
            
            if s.rPref[proposer] < s.rPref[s.proposer] {
                fmt.Println("engagement broken:", recipient, s.proposer)
                
                pFree[s.proposer] = s.pPref 
                
                rpref = s.rPref
                
            } else {
                
                pFree[proposer] = ppref 
                continue
            } 
        }
        fmt.Println("engagement:", recipient, proposer)
        proposals[recipient] = save{proposer, ppref, rpref}
        delete(pFree, proposer)
        delete(rFree, recipient)
    }
    
    ps := parings{}
    for recipient, s := range proposals {
        ps[recipient] = s.proposer
    }
    return ps
}

func validateStable(ps parings, pPref proposers, rPref recipients) bool {
    for r, p := range ps {
        fmt.Println(r, p)
    }
    for r, p := range ps {
        for _, rp := range pPref[p] {
            if rp == r {
                break
            }
            rprefs := rPref[rp]
            if rprefs[p] < rprefs[ps[rp]] {
                fmt.Println("unstable.")
                fmt.Printf("%s and %s would prefer each other over"+
                    " their current pairings.\n", p, rp)
                return false
            }
        }
    }
    fmt.Println("stable.")
    return true
}





VB: Sub M_snb()
  c00 = "_abe abi eve cath ivy jan dee fay bea hope gay " & _
        "_bob cath hope abi dee eve fay bea jan ivy gay " & _
        "_col hope eve abi dee bea fay ivy gay cath jan " & _
        "_dan ivy fay dee gay hope eve jan bea cath abi " & _
        "_ed jan dee bea cath fay eve abi ivy hope gay " & _
        "_fred bea abi dee gay eve ivy cath jan hope fay " & _
        "_gav gay eve ivy bea cath abi dee hope jan fay " & _
        "_hal abi eve hope fay ivy cath jan bea gay dee " & _
        "_ian hope cath dee gay bea abi fay ivy jan eve " & _
        "_jon abi fay jan gay eve bea dee cath ivy hope " & _
        "_abi bob fred jon gav ian abe dan ed col hal " & _
        "_bea bob abe col fred gav dan ian ed jon hal " & _
        "_cath fred bob ed gav hal col ian abe dan jon " & _
        "_dee fred jon col abe ian hal gav dan bob ed " & _
        "_eve jon hal fred dan abe gav col ed ian bob " & _
        "_fay bob abe ed ian jon dan fred gav col hal " & _
        "_gay jon gav hal fred bob abe col ed dan ian " & _
        "_hope gav jon bob abe ian dan hal ed col fred " & _
        "_ivy ian col hal gav fred bob abe ed jon dan " & _
        "_jan ed hal gav abe bob jon col ian fred dan "
     
  sn = Filter(Filter(Split(c00), "_"), "-", 0)
  Do
    c01 = Mid(c00, InStr(c00, sn(0) & " "))
    st = Split(Left(c01, InStr(Mid(c01, 2), "_")))
      For j = 1 To UBound(st) - 1
        If InStr(c00, "_" & st(j) & " ") > 0 Then
          c00 = Replace(Replace(c00, sn(0), sn(0) & "-" & st(j)), "_" & st(j), "_" & st(j) & "." & Mid(sn(0), 2))
          Exit For
        Else
          c02 = Filter(Split(c00, "_"), st(j) & ".")(0)
          c03 = Split(Split(c02)(0), ".")(1)
          If InStr(c02, " " & Mid(sn(0), 2) & " ") < InStr(c02, " " & c03 & " ") Then
            c00 = Replace(Replace(Replace(c00, c03 & "-" & st(j), c03), sn(0), sn(0) & "-" & st(j)), "_" & st(j), "_" & st(j) & "." & Mid(sn(0), 2))
            Exit For
          End If
        End If
     Next
     sn = Filter(Filter(Filter(Split(c00), "_"), "-", 0), ".", 0)
   Loop Until UBound(sn) = -1
   
   MsgBox Replace(Join(Filter(Split(c00), "-"), vbLf), "_", "")
End Sub