1 files changed, 24 insertions, 0 deletions
diff --git a/src/gobang.go b/src/gobang.go
index 2985d19..1826a5f 100644
--- a/src/gobang.go
+++ b/src/gobang.go
@@ -65,6 +65,30 @@ var (
 
 
 
+func MapIndexed[A any, B any](fn func(A, int) B, coll []A) []B {
+	out := make([]B, len(coll))
+	for i, x := range coll {
+		out[i] = fn(x, i)
+	}
+	return out
+}
+
+func Map[A any, B any](fn func(A) B, coll []A) []B {
+	return MapIndexed(func(x A, _ int) B {
+		return fn(x)
+	}, coll)
+}
+
+func Filter[A any](fn func(A) bool, coll []A) []A {
+	out := []A{}
+	for _, x := range coll {
+		if fn(x) {
+			out = append(out, x)
+		}
+	}
+	return out
+}
+
 func PanicIf(err error) {
 	if err != nil {
 		panic(err)