message: Update find-the-k-beauty-of-a-number.cpp
diff: @@ -6,8 +6,8 @@ class Solution {
  public:
  int divisorSubstrings(int num, int k) {
  int result = 0;
  - string s = to_string(num);
  - int base = pow(10, k - 1);
  + const auto& s = to_string(num);
  + const int base = pow(10, k - 1);
  for (int i = 0, curr = 0; i < size(s); ++i) {
  if (i - k >= 0) {
  curr -= (s[i - k] - '0') * base;
  