Day379

README.md

@@ -374,4 +374,5 @@ problems from
 * [Day 376](https://github.com/vaskoz/dailycodingproblem-go/issues/758)
 * [Day 377](https://github.com/vaskoz/dailycodingproblem-go/issues/760)
 * [Day 378](https://github.com/vaskoz/dailycodingproblem-go/issues/762)
+* [Day 379](https://github.com/vaskoz/dailycodingproblem-go/issues/764)
 

day379/problem.go

@@ -0,0 +1,23 @@
+package day379
+
+// AllPossibleSubsequences returns all the possible
+// ordered subsequences.
+func AllPossibleSubsequences(str string) map[string]struct{} {
+	ansSet := make(map[string]struct{})
+	allPossibleSubsequences(str, ansSet)
+
+	return ansSet
+}
+
+func allPossibleSubsequences(str string, ansSet map[string]struct{}) {
+	if _, alreadyExists := ansSet[str]; len(str) == 0 || alreadyExists {
+		return
+	}
+
+	for i := range str {
+		sub := str[:i] + str[i+1:]
+		allPossibleSubsequences(sub, ansSet)
+	}
+
+	ansSet[str] = struct{}{}
+}

day379/problem_test.go

@@ -0,0 +1,41 @@
+package day379
+
+import (
+	"reflect"
+	"testing"
+)
+
+// nolint
+var testcases = []struct {
+	input  string
+	subseq map[string]struct{}
+}{
+	{"xyz",
+		map[string]struct{}{
+			"x":   {},
+			"y":   {},
+			"z":   {},
+			"xy":  {},
+			"xz":  {},
+			"yz":  {},
+			"xyz": {},
+		}},
+}
+
+func TestAllPossibleSubsequences(t *testing.T) {
+	t.Parallel()
+
+	for _, tc := range testcases {
+		if result := AllPossibleSubsequences(tc.input); !reflect.DeepEqual(result, tc.subseq) {
+			t.Errorf("Expected %v, got %v", tc.subseq, result)
+		}
+	}
+}
+
+func BenchmarkAllPossibleSubsequences(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range testcases {
+			AllPossibleSubsequences(tc.input)
+		}
+	}
+}