message: Update valid-anagram.cpp
diff: class Solution {
  public:
  bool isAnagram(string s, string t) {
  - if (s.length() != t.length()) {
  + if (size(s) != size(t)) {
  return false;
  }
  unordered_map<char, int> count;
  -
  for (const auto& c: s) {
  - ++count[tolower(c)];
  + ++count[c];
  }
  -
  for (const auto& c: t) {
  - --count[tolower(c)];
  - if (count[tolower(c)] < 0) {
  + --count[c];
  + if (count[c] < 0) {
  return false;
  }
  }
  -
  return true;
  }
  };
  // Time: O(nlogn)
  -// Space: O(n)
  +// Space: O(1)
  class Solution2 {
  public:
  bool isAnagram(string s, string t) {
  - if (s.length() != t.length()) {
  + if (size(s) != size(t)) {
  return false;
  }
  - sort(s.begin(), s.end());
  - sort(t.begin(), t.end());
  -
  + sort(begin(s), end(s));
  + sort(begin(t), end(t));
  return s == t;
  }
  };
  