fix: stv vote

comsoc/STV.go

 package comsoc
 
+func getRandomKey(count Count) Alternative {
+	for k := range count {
+		return k
+	}
+	return 0 // should never happen
+}
+
+func countContains(count Count, alt Alternative) bool {
+	for k := range count {
+		if alt == k {
+			return true
+		}
+	}
+	return false
+}
+
 // renvoie une des pires alternatives pour un décompte donné
-func minCount(count Count) (worstAlt Alternative) {
-	minPoints := count[Alternative(1)]
+func minCount(count Count, alts []Alternative) (worstAlt Alternative) {
+	for _, alt := range alts {
+		if !countContains(count, alt) {
+			return alt
+		}
+	}
+	worstAlt = getRandomKey(count)
+	minPoints := count[worstAlt]
 	for i, points := range count {
 		if points < minPoints {
-			worstAlt = Alternative(i)
+			worstAlt = i
 			minPoints = points
 		}
 	}
@@ -22,14 +44,25 @@ func STV_SWF(p Profile) (count Count, err error) {
 	if err != nil {
 		return nil, err
 	}
-	for round := 0; round < len(alts)-1; round++ {
-		majorityRes, _ := MajoritySWF(p)
-		worstAlt := minCount(majorityRes)
-		count[worstAlt] = round
+
+	nbRounds := len(alts)
+	for round := 0; round < nbRounds; round++ {
+		majorityRes := make(Count)
 		for _, pref := range p {
-			toDelRank := rank(worstAlt, pref)
-			pref[toDelRank] = pref[len(pref)-1]
+			majorityRes[pref[0]]++
+		}
+		worstAlt := minCount(majorityRes, alts)
+		count[worstAlt] = round
+
+		// On enlève la pire alt des alts
+		alts[rank(worstAlt, alts)] = alts[len(alts)-1]
+		alts = alts[:len(alts)-1]
+
+		// on enlève la pire alt de chacunes des preferences
+		for i, pref := range p {
+			pref[rank(worstAlt, pref)] = pref[len(pref)-1]
 			pref = pref[:len(pref)-1]
+			p[i] = pref
 		}
 	}
 	return