/in/foo.cc: In function 'void insert(arr)':
/in/foo.cc:21:12: warning: operation on 'sz' may be undefined [-Wsequence-point]
  nxt[sz] = ++sz;
            ^~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:34:18: warning: format '%lld' expects argument of type 'long long int*', but argument 2 has type 'int*' [-Wformat=]
  scanf("%lld", &n);
                  ^
/in/foo.cc:36:23: warning: format '%lld' expects argument of type 'long long int*', but argument 2 has type 'int*' [-Wformat=]
   scanf("%lld", s1 + i);
                       ^
/in/foo.cc:38:23: warning: format '%lld' expects argument of type 'long long int*', but argument 2 has type 'int*' [-Wformat=]
   scanf("%lld", s2 + i);
                       ^
/in/foo.cc:66:23: warning: format '%lld' expects argument of type 'long long int', but argument 2 has type 'int' [-Wformat=]
   printf("%lld\n", ans);
                       ^