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class Solution {
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  int first_diff(string s) {
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    for (int i = 0; i < (s.size() + 1) / 2; ++i) {
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      if (s[i] != s[s.size() - 1 - i]) {
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        return i;
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      }
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    }
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    return -1;
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  }
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 public:
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  bool validPalindrome(string s) {
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    int diff = first_diff(s);
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    if (diff == -1 || (s.size() % 2 == 0 && diff + 1 == s.size() / 2)) {
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      // abca. If we have pattern like this than we can delete one of the
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      // symbols
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      return true;
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    }
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    bool first_valid = true;
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    for (int i = diff; i < (s.size() + 1) / 2; ++i) {
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      if (s[i] != s[s.size() - 2 - i]) {
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        first_valid = false;
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        break;
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      }
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    }
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    bool second_valid = true;
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    for (int i = diff; i < (s.size() + 1) / 2; ++i) {
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      if (s[i + 1] != s[s.size() - 1 - i]) {
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        second_valid = false;
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        break;
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      }
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    }
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    return first_valid || second_valid;
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  }
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};