/in/foo.cc: In function 'int z(int, int)':
/in/foo.cc:15:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0;i<strlen(s[num]);i++)
               ~^~~~~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:38:16: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[20]' [-Wformat=]
   scanf("%s",&t);
                ^
/in/foo.cc:40:16: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[20]' [-Wformat=]
   scanf("%s",&t);
                ^
/in/foo.cc:66:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   if (i==n-1) printf("%d\n",max(R,0));return 0;
   ^~
/in/foo.cc:66:39: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
   if (i==n-1) printf("%d\n",max(R,0));return 0;
                                       ^~~~~~