algos permutation method names changed to algos.PermuteTYPE

2016/day21/main.go

@@ -39,7 +39,7 @@ func part1(input string, starting string, target string) string {
 		return runSteps(starting)
 	}
 
-	for _, p := range algos.MakeStringPermutations(starting) {
+	for _, p := range algos.PermuteString(starting) {
 		if runSteps(p) == target {
 			return p
 		}

2019/day07/part1/main.go

@@ -22,7 +22,7 @@ func main() {
 	}
 
 	// Make perms via a util function
-	perms := algos.MakeIntPermutations([]int{0, 1, 2, 3, 4})
+	perms := algos.PermuteIntSlice([]int{0, 1, 2, 3, 4})
 
 	// iterate over all perms and run through a single pass of the Amps
 	// if the final output (from Amp E) is higher, update the highestOutput variable

2019/day07/part2/main.go

@@ -22,7 +22,7 @@ func main() {
 	}
 
 	// Make perms via a util function
-	perms := algos.MakeIntPermutations([]int{5, 6, 7, 8, 9})
+	perms := algos.PermuteIntSlice([]int{5, 6, 7, 8, 9})
 
 	// iterate over all perms and run through a single pass of the Amps
 	// if the final output (from Amp E) is higher, update the highestOutput variable

algos/permutations.go

@@ -2,13 +2,13 @@ package algos
 
 import "strings"
 
-// MakeIntPermutations will make all permutations of the numbers input
+// PermuteIntSlice will make all permutations of the numbers input
-func MakeIntPermutations(numbers []int) [][]int {
+func PermuteIntSlice(numbers []int) [][]int {
-	return recurseInts(numbers, 0)
+	return recurseIntSlice(numbers, 0)
 }
 
 // helper function to generate permutations
-func recurseInts(numbers []int, startIndex int) [][]int {
+func recurseIntSlice(numbers []int, startIndex int) [][]int {
 	if startIndex == len(numbers) {
 		// makes a copy using append
 		return [][]int{append([]int{}, numbers...)}
@@ -18,18 +18,18 @@ func recurseInts(numbers []int, startIndex int) [][]int {
 	for i := startIndex; i < len(numbers); i++ {
 		// swap, append perms, backtrack
 		numbers[startIndex], numbers[i] = numbers[i], numbers[startIndex]
-		perms = append(perms, recurseInts(numbers, startIndex+1)...)
+		perms = append(perms, recurseIntSlice(numbers, startIndex+1)...)
 		numbers[startIndex], numbers[i] = numbers[i], numbers[startIndex]
 	}
 	return perms
 }
 
-// MakeStringPermutations generates all permutations for a given string
+// PermuteString generates all permutations for a given string
-func MakeStringPermutations(str string) []string {
+func PermuteString(str string) []string {
-	return recurseStrings(strings.Split(str, ""), 0)
+	return recurseString(strings.Split(str, ""), 0)
 }
 
-func recurseStrings(sli []string, index int) []string {
+func recurseString(sli []string, index int) []string {
 	if index == len(sli) {
 		return []string{strings.Join(sli, "")}
 	}
@@ -37,8 +37,30 @@ func recurseStrings(sli []string, index int) []string {
 	var perms []string
 	for i := index; i < len(sli); i++ {
 		sli[i], sli[index] = sli[index], sli[i]
-		perms = append(perms, recurseStrings(sli, index+1)...)
+		perms = append(perms, recurseString(sli, index+1)...)
 		sli[i], sli[index] = sli[index], sli[i]
 	}
 	return perms
 }
+
+// PermuteStringSlice will make all permutations of a string slice
+func PermuteStringSlice(in []string) [][]string {
+	return recurseStringsSlice(in, 0)
+}
+
+// helper function to generate permutations
+func recurseStringsSlice(in []string, startIndex int) [][]string {
+	if startIndex == len(in) {
+		// makes a copy using append
+		return [][]string{append([]string{}, in...)}
+	}
+
+	var perms [][]string
+	for i := startIndex; i < len(in); i++ {
+		// swap, append perms, backtrack
+		in[startIndex], in[i] = in[i], in[startIndex]
+		perms = append(perms, recurseStringsSlice(in, startIndex+1)...)
+		in[startIndex], in[i] = in[i], in[startIndex]
+	}
+	return perms
+}