Palindrome check
A puzzle feature checks whether a phrase reads the same backwards.
- Compare letters and digits only — skip spaces and punctuation.
- Case does not matter.
- An empty string counts as a palindrome.
isPalindrome(text: string) → bool
Go needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
func isPalindrome(text string) bool {
}Worked examples
| Call | Result |
|---|---|
isPalindrome("") | true |
isPalindrome("racecar") | true |
isPalindrome("A man, a plan, a canal: Panama") | true |
isPalindrome("hello") | false |
Hint
Walk one index from each end, skipping anything that is not alphanumeric.
Reference solution in Go
func isPalindrome(text string) bool {
clean := []rune{}
for _, c := range strings.ToLower(text) {
if (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') {
clean = append(clean, c)
}
}
for i, j := 0, len(clean)-1; i < j; i, j = i+1, j-1 {
if clean[i] != clean[j] {
return false
}
}
return true
}