36: double-base palindromes

36_double_base_palindromes/main.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	sum := 0
+	for i := 0; i < 1e6; i++ {
+		if isPalindromeDecimal(i) && isPalindromeString(convertToBinary(i)) {
+			sum += i
+		}
+	}
+	fmt.Println("sum:", sum)
+}
+
+func isPalindromeDecimal(n int) bool {
+	return isPalindromeString(strconv.Itoa(n))
+}
+
+func convertToBinary(num int) string {
+	s := ""
+	if num == 0 {
+		return "0"
+	}
+	for ; num > 0; num /= 2 {
+		lsb := num % 2
+		s = strconv.Itoa(lsb) + s
+	}
+	return s
+}
+
+func isPalindromeString(s string) bool {
+	pb := strings.Builder{}
+	for i := len(s); i > 0; i-- {
+		pb.WriteString(s[i-1 : i])
+	}
+	pstr := pb.String()
+	return s == pstr
+}