only check bitlen once

03/main.go

@@ -62,12 +62,14 @@ func partTwo() {
 	inputs := []int64{}
 	var oxgen, co2scrub int64
 
-	var bitlen int64
+	var bitlen int
 	for scanner.Scan() {
 		line := scanner.Text()
+		if bitlen == 0 {
+			bitlen = len(line)
+		}
 		n, _ := strconv.ParseInt(line, 2, 64)
 		inputs = append(inputs, n)
-		bitlen = int64(len(line))
 	}
 
 	// on initial loop, oxgen>>i == n>>i etc always come out to 0 == 0