2020 Day 21 Complete

helpers/helpers.go

@@ -252,6 +252,15 @@ func IntSlicesAreEqual(s1 []int, s2 []int) bool {
 	return true
 }
 
+func StringSliceIndex(h []string, n string) int {
+	for k, v := range h {
+		if v == n {
+			return k
+		}
+	}
+	return -1
+}
+
 // StringSliceContains takes a string slice and a string and return true
 // if the string is in the slice
 func StringSliceContains(h []string, n string) bool {
@@ -282,6 +291,46 @@ func AppendStrings(base string, group []string) []string {
 	return group
 }
 
+// UnionStringSlice returns a slice that combines list1 and list2
+func UnionStringSlice(list1, list2 []string) []string {
+	for k := range list1 {
+		if !StringSliceContains(list2, list1[k]) {
+			list2 = append(list2, list1[k])
+		}
+	}
+	return list2
+}
+
+// IntersectStringSlice returns a slice that contains all elements that
+// both list1 and list2 contain
+func IntersectStringSlice(list1, list2 []string) []string {
+	var ret []string
+	for k := range list1 {
+		if StringSliceContains(list2, list1[k]) {
+			ret = append(ret, list1[k])
+		}
+	}
+	return ret
+}
+
+// Unique removes all duplicates
+func UniqueStringSlice(list []string) []string {
+	var ret []string
+	for k := 0; k < len(list); k++ {
+		var dupe bool
+		for j := k; j < len(list); j++ {
+			if list[k] == list[j] {
+				dupe = true
+				break
+			}
+		}
+		if !dupe {
+			ret = append(ret, list[k])
+		}
+	}
+	return ret
+}
+
 // IsPrime takes a number and return true if that number is prime
 func IsPrime(value int) bool {
 	for i := 2; i <= int(math.Floor(float64(value)/2)); i++ {