/in/foo.cc: In function 'int main()':
/in/foo.cc:11:6: warning: unused variable 'i' [-Wunused-variable]
  int i, j, k, t;
      ^
/in/foo.cc:11:9: warning: unused variable 'j' [-Wunused-variable]
  int i, j, k, t;
         ^
/in/foo.cc:11:12: warning: unused variable 'k' [-Wunused-variable]
  int i, j, k, t;
            ^
/in/foo.cc: In function 'int kmp()':
/in/foo.cc:38:12: warning: unused variable 'k' [-Wunused-variable]
  int i, j, k, ans = 0;
            ^
/in/foo.cc:38:15: warning: unused variable 'ans' [-Wunused-variable]
  int i, j, k, ans = 0;
               ^~~