diff --git a/number-of-valid-words-for-each-puzzle/sol.go b/number-of-valid-words-for-each-puzzle/sol.go
new file mode 100644
index 0000000..548d3d1
--- /dev/null
+++ b/number-of-valid-words-for-each-puzzle/sol.go
@@ -0,0 +1,30 @@
+package main
+
+func mask(str string) int {
+	mask := 0
+	for _, r := range str {
+		mask |= 1 << (r - 'a')
+	}
+	return mask
+}
+
+func findNumOfValidWords(words []string, puzzles []string) []int {
+	word_masks := make(map[int]int)
+	for _, word := range words {
+		mask := mask(word)
+		word_masks[mask] += 1
+	}
+
+	out := make([]int, len(puzzles))
+	for pi, puzzle := range puzzles {
+		pc := mask(puzzle[1:])
+		fc := 1 << (puzzle[0] - 'a')
+		count, submask := word_masks[fc], pc
+		for submask != 0 {
+			count += word_masks[submask|fc]
+			submask = (submask - 1) & pc
+		}
+		out[pi] = count
+	}
+	return out
+}