foo.cc: In function 'int main()':
foo.cc:27:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   27 |         int l, r; scanf ( "%d%d", &l, &r );
      |                   ~~~~~~^~~~~~~~~~~~~~~~~~
foo.cc: In function 'void KMP()':
foo.cc:11:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |     scanf ( "%d%d%d%s%s", &la, &lb, &q, a + 1, b + 1 );
      |     ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务