snippets

#include <string>

bool isPalindrome(const std::string& s) {
    int lo = 0, hi = (int)s.size() - 1;
    while (lo < hi) {
        while (lo < hi && !isalnum(s[lo])) ++lo;
        while (lo < hi && !isalnum(s[hi])) --hi;
        if (tolower(s[lo++]) != tolower(s[hi--])) return false;
    }
    return true;
}