All O(1) are not same sample code 1

isAnagramNlogN.cpp

bool isAnagram(const std::string& str1, const std::string& str2){
  // Two string can't be anagram if they are of different size [O(1)]
  if(str1.size()!=str2.size()){
    return false;
  }

  // Copy have to be done to sort it later [O(n) space and O(n) time both]
  std::string str1Copy = str1;
  std::string str2Copy = str2;

  // C++ sort implementation [O(nlogn)]
  std::sort(str1Copy.begin(), str1Copy.end());
  std::sort(str2Copy.begin(), str2Copy.end());

  // Final search [O(n)]
  return str1Copy==str2Copy;
}