Fix infinite loop

Co-authored-by: David Schlachter <https://github.com/davidschlachter>

flake.nix

@@ -80,6 +80,7 @@
           clean
 
           go
+          gofumpt
         ]);
 
         shellHook = ''

src/l33tcode/841.go

@@ -3,7 +3,7 @@ package main
 import "fmt"
 
 func main() {
-	res := canVisitAllRooms([][]int{{1}, {2}, {}})
+	res := canVisitAllRooms([][]int{{1, 3}, {3, 0, 1}, {2}, {0}})
 	fmt.Printf("%+v\n", res)
 }
 
@@ -27,11 +27,13 @@ func getAllKeys(index int, seen map[int]struct{}, rooms [][]int) map[int]struct{
 	keys := map[int]struct{}{}
 
 	for j := 0; j < len(rooms[index]); j++ {
-			if _, ok := keys[rooms[index][j]]; ok {
+		if _, ok := seen[rooms[index][j]]; ok {
 			continue
+		} else {
+			seen[rooms[index][j]] = struct{}{}
 		}
 		keys[rooms[index][j]] = struct{}{}
-			insideKeys := getAllKeys(j, keys, rooms)
+		insideKeys := getAllKeys(rooms[index][j], seen, rooms)
 		for k := range insideKeys {
 			keys[k] = struct{}{}
 		}