[Grind 169] 5. Valid Palindrome

Problem Link: https://leetcode.com/problems/valid-palindrome/

Solution:

func isPalindrome(s string) bool {
    var sb strings.Builder

    for _, c := range s {
        var str = string(c)
        if (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') {
            sb.WriteString(str)
        } else if (c >= 'A' && c <= 'Z') {
            sb.WriteString(strings.ToLower(str)) 
        }
    }

    s = sb.String()
    var n = len(s)

    for i := 0; i < n/2; i++ {
        if s[i] != s[n-i-1]  {
           return false 
        }
    }

    return true
}