1
class Solution {
2
 public:
3
  bool isPalindrome(string s) {
4
    auto it = remove_if(s.begin(), s.end(), [](char const &c) { return !isalnum(c); });
5

6
    s.erase(it, s.end());
7
    transform(s.begin(), s.end(), s.begin(), ::tolower);
8

9
    int i = 0;
10
    int j = s.size() - 1;
11

12
    while (i <= j) {
13
      if (s[i] != s[j]) return false;
14
      i++;
15
      j--;
16
    }
17

18
    return true;
19
  }
20
};